No snapshot cached for ... - avoidSnapshotBatteryDrain: true - snapshot lifetime over 2 minutes?
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# Bug Report

### Describe the Bug
No snapshot cached for ... with `avoidSnapshotBatteryDrain: true` in `config.json`. Snapshot lifetime longer as 2 minutes?

### To Reproduce
Restart Homebridge, snapshots are okay, after 2 minutes with `avoidSnapshotBatteryDrain: true`, `No snapshot cached for ...`, after 10 minutes, new snapshot cached, after 2 minutes, `No snapshot cached for ...`, ...

### Expected behavior
#### Ring Spotlight Cam Wired (hp_cam_v2) 
- Name: Garten 
- ALL IS OK ✅
- `avoidSnapshotBatteryDrain` has no effect ✅
- Snapshots ok ✅

#### Ring Stick Up Cam Wired (cocoa_camera)
- Name: Kinderzimmer Felix 
- Not ok, is plug-in - `avoidSnapshotBatteryDrain` should have no effect ❌
- Check if "_Battery-Mode_" or "_Plug-In_"?

#### Ring Video Doorbell 3 Plus (doorbell_scallop) 
- Name: Haustür 
- Is hardwired, but battery
- `avoidSnapshotBatteryDrain` has effect ✅
- Snapshot lifetime only 2 minutes
- Snapshot lifetime longer as 2 minutes, with battery devices with active `avoidSnapshotBatteryDrain`? ❌


### Screenshots/Logs
```
Nov 26 15:49:42 frida homebridge[27530]: [2020-11-26 15:49:42] Homebridge is running on port 51829.
Nov 26 15:49:45 frida homebridge[27530]: [2020-11-26 15:49:45] [Ring] Location Mode: {"mode":"unset","lastUpdateTimeMS":1606207317019,"securityStatus":{},"readOnly":true,"notYetParticipatingInMode":[],"responseTimestamp":1606402185000}
Nov 26 15:49:45 frida homebridge[27530]: [2020-11-26 15:49:45] [Ring] Configuring 3 cameras and 4 devices for location "Münchberg" - locationId: 1234abcd-9876...
Nov 26 15:49:54 frida homebridge[27530]: [2020-11-26 15:49:54] [Ring] No snapshot cached for Garten
Nov 26 15:49:54 frida homebridge[27530]: [2020-11-26 15:49:54] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:49:56 frida homebridge[27530]: [2020-11-26 15:49:56] [Ring] Snapshot cached for Garten (1.74s)
Nov 26 15:50:04 frida homebridge[27530]: [2020-11-26 15:50:04] [Ring] No snapshot cached for Haustür
Nov 26 15:50:04 frida homebridge[27530]: [2020-11-26 15:50:04] [Ring] Loading new snapshot into cache for Haustür
Nov 26 15:50:04 frida homebridge[27530]: [2020-11-26 15:50:04] [Ring] No snapshot cached for Kinderzimmer Felix
Nov 26 15:50:04 frida homebridge[27530]: [2020-11-26 15:50:04] [Ring] Loading new snapshot into cache for Kinderzimmer Felix
Nov 26 15:50:04 frida homebridge[27530]: [2020-11-26 15:50:04] [Ring] Snapshot cached for Haustür (0.231s)
Nov 26 15:50:04 frida homebridge[27530]: [2020-11-26 15:50:04] [Ring] Snapshot cached for Kinderzimmer Felix (0.237s)
Nov 26 15:50:14 frida homebridge[27530]: [2020-11-26 15:50:14] [Ring] Used cached snapshot for Garten
Nov 26 15:50:14 frida homebridge[27530]: [2020-11-26 15:50:14] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:50:17 frida homebridge[27530]: [2020-11-26 15:50:17] [Ring] Snapshot cached for Garten (2.382s)
Nov 26 15:50:24 frida homebridge[27530]: [2020-11-26 15:50:24] [Ring] Used cached snapshot for Garten
Nov 26 15:50:34 frida homebridge[27530]: [2020-11-26 15:50:34] [Ring] Used cached snapshot for Garten
Nov 26 15:50:34 frida homebridge[27530]: [2020-11-26 15:50:34] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:50:36 frida homebridge[27530]: [2020-11-26 15:50:36] [Ring] Snapshot cached for Garten (1.757s)
Nov 26 15:50:44 frida homebridge[27530]: [2020-11-26 15:50:44] [Ring] Used cached snapshot for Garten
Nov 26 15:50:54 frida homebridge[27530]: [2020-11-26 15:50:54] [Ring] Used cached snapshot for Haustür
Nov 26 15:50:54 frida homebridge[27530]: [2020-11-26 15:50:54] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:50:54 frida homebridge[27530]: [2020-11-26 15:50:54] [Ring] Used cached snapshot for Garten
Nov 26 15:50:54 frida homebridge[27530]: [2020-11-26 15:50:54] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:50:56 frida homebridge[27530]: [2020-11-26 15:50:56] [Ring] Snapshot cached for Garten (1.611s)
Nov 26 15:51:04 frida homebridge[27530]: [2020-11-26 15:51:04] [Ring] Used cached snapshot for Haustür
Nov 26 15:51:04 frida homebridge[27530]: [2020-11-26 15:51:04] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:51:05 frida homebridge[27530]: [2020-11-26 15:51:05] [Ring] Used cached snapshot for Garten
Nov 26 15:51:14 frida homebridge[27530]: [2020-11-26 15:51:14] [Ring] Used cached snapshot for Haustür
Nov 26 15:51:14 frida homebridge[27530]: [2020-11-26 15:51:14] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:51:15 frida homebridge[27530]: [2020-11-26 15:51:15] [Ring] Used cached snapshot for Garten
Nov 26 15:51:15 frida homebridge[27530]: [2020-11-26 15:51:15] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:51:18 frida homebridge[27530]: [2020-11-26 15:51:18] [Ring] Snapshot cached for Garten (2.885s)
Nov 26 15:51:24 frida homebridge[27530]: [2020-11-26 15:51:24] [Ring] Used cached snapshot for Haustür
Nov 26 15:51:24 frida homebridge[27530]: [2020-11-26 15:51:24] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:51:25 frida homebridge[27530]: [2020-11-26 15:51:25] [Ring] Used cached snapshot for Garten
Nov 26 15:51:34 frida homebridge[27530]: [2020-11-26 15:51:34] [Ring] Used cached snapshot for Haustür
Nov 26 15:51:34 frida homebridge[27530]: [2020-11-26 15:51:34] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:51:35 frida homebridge[27530]: [2020-11-26 15:51:35] [Ring] Used cached snapshot for Garten
Nov 26 15:51:35 frida homebridge[27530]: [2020-11-26 15:51:35] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:51:36 frida homebridge[27530]: [2020-11-26 15:51:36] [Ring] Snapshot cached for Garten (1.608s)
Nov 26 15:51:44 frida homebridge[27530]: [2020-11-26 15:51:44] [Ring] Used cached snapshot for Haustür
Nov 26 15:51:44 frida homebridge[27530]: [2020-11-26 15:51:44] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:51:45 frida homebridge[27530]: [2020-11-26 15:51:45] [Ring] Used cached snapshot for Garten
Nov 26 15:51:54 frida homebridge[27530]: [2020-11-26 15:51:54] [Ring] Used cached snapshot for Haustür
Nov 26 15:51:54 frida homebridge[27530]: [2020-11-26 15:51:54] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:51:55 frida homebridge[27530]: [2020-11-26 15:51:55] [Ring] Used cached snapshot for Garten
Nov 26 15:51:55 frida homebridge[27530]: [2020-11-26 15:51:55] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:51:57 frida homebridge[27530]: [2020-11-26 15:51:57] [Ring] Snapshot cached for Garten (1.649s)
Nov 26 15:52:04 frida homebridge[27530]: [2020-11-26 15:52:04] [Ring] No snapshot cached for Haustür
Nov 26 15:52:04 frida homebridge[27530]: [2020-11-26 15:52:04] [Ring] No snapshot cached for Kinderzimmer Felix
Nov 26 15:52:05 frida homebridge[27530]: [2020-11-26 15:52:05] [Ring] Used cached snapshot for Garten
Nov 26 15:52:14 frida homebridge[27530]: [2020-11-26 15:52:14] [Ring] No snapshot cached for Haustür
Nov 26 15:52:14 frida homebridge[27530]: [2020-11-26 15:52:14] [Ring] No snapshot cached for Kinderzimmer Felix
Nov 26 15:52:15 frida homebridge[27530]: [2020-11-26 15:52:15] [Ring] Used cached snapshot for Garten
Nov 26 15:52:15 frida homebridge[27530]: [2020-11-26 15:52:15] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:52:17 frida homebridge[27530]: [2020-11-26 15:52:17] [Ring] Snapshot cached for Garten (2.319s)
Nov 26 15:52:25 frida homebridge[27530]: [2020-11-26 15:52:25] [Ring] Used cached snapshot for Garten
Nov 26 15:52:34 frida homebridge[27530]: [2020-11-26 15:52:34] [Ring] No snapshot cached for Haustür
Nov 26 15:52:35 frida homebridge[27530]: [2020-11-26 15:52:35] [Ring] No snapshot cached for Kinderzimmer Felix
...
Nov 26 15:56:22 frida homebridge[27530]: [2020-11-26 15:56:22] [Ring] No snapshot cached for Kinderzimmer Felix
Nov 26 15:56:22 frida homebridge[27530]: [2020-11-26 15:56:22] [Ring] Loading new snapshot into cache for Kinderzimmer Felix
Nov 26 15:56:22 frida homebridge[27530]: [2020-11-26 15:56:22] [Ring] No snapshot cached for Haustür
Nov 26 15:56:22 frida homebridge[27530]: [2020-11-26 15:56:22] [Ring] Loading new snapshot into cache for Haustür
Nov 26 15:56:23 frida homebridge[27530]: [2020-11-26 15:56:23] [Ring] Snapshot cached for Garten (1.716s)
Nov 26 15:56:23 frida homebridge[27530]: [2020-11-26 15:56:23] [Ring] Snapshot cached for Kinderzimmer Felix (1.533s)
Nov 26 15:56:26 frida homebridge[27530]: [2020-11-26 15:56:26] [Ring] Used cached snapshot for Garten
Nov 26 15:56:27 frida homebridge[27530]: [2020-11-26 15:56:27] [Ring] Snapshot cached for Haustür (4.775s)
Nov 26 15:56:31 frida homebridge[27530]: [2020-11-26 15:56:31] [Ring] Used cached snapshot for Garten
Nov 26 15:56:36 frida homebridge[27530]: [2020-11-26 15:56:36] [Ring] Used cached snapshot for Garten
Nov 26 15:56:36 frida homebridge[27530]: [2020-11-26 15:56:36] [Ring] Loading new snapshot into cache for Garten
Nov 26 15:56:38 frida homebridge[27530]: [2020-11-26 15:56:38] [Ring] Snapshot cached for Garten (1.811s)
Nov 26 15:56:41 frida homebridge[27530]: [2020-11-26 15:56:41] [Ring] Used cached snapshot for Garten
Nov 26 15:56:42 frida homebridge[27530]: [2020-11-26 15:56:42] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:56:42 frida homebridge[27530]: [2020-11-26 15:56:42] [Ring] Used cached snapshot for Haustür
Nov 26 15:56:45 frida homebridge[27530]: [2020-11-26 15:56:45] [Ring] Used cached snapshot for Haustür
Nov 26 15:56:45 frida homebridge[27530]: [2020-11-26 15:56:45] [Ring] Used cached snapshot for Kinderzimmer Felix
Nov 26 15:56:47 frida homebridge[27530]: [2020-11-26 15:56:47] [Ring] Used cached snapshot for Garten
...
```

### Homebridge Ring Config
```
{
      "platform": "Ring",
      "refreshToken": "xyz",
      "hideDoorbellSwitch": true,
      "hideInHomeDoorbellSwitch": false,
      "hideCameraMotionSensor": false,
      "cameraStatusPollingSeconds": 20,
      "cameraDingsPollingSeconds": 2,
      "avoidSnapshotBatteryDrain": true,
      "debug": true
    }
```

### Environment
 - OS: Debian 10.6
 - Node.js: v12.19.0
 - NPM: 6.14.9
 - homebridge-ring: 9.12.6
 - homebridge: 1.1.6