Inconsistency with ObjectSensors
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**Describe The Problem:**
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I have two cameras attached to my Protect system, both with their own defined Smart Detection Zones, that accurately record People/Vehicle detections. 

I also have ` "Enable.Motion.SmartDetect.ObjectSensors"` in my plugin config. When Homebridge reboots, it's hit or miss whether the object sensors for vehicles or people are added along with the cameras themselves. Sometimes they both show up for both cameras, more frequently none of them show up, and sometimes one will show up for one camera, and one for another camera.  

**To Reproduce:**
<!-- Steps to reproduce the behavior. -->

- Add ` "Enable.Motion.SmartDetect.ObjectSensors"` to your config. 
- Make sure Smart Detection is on for the cameras in question in Protect. (this behavior seems to occur whether the recording is set to `always` or `smart detections`)
- Reboot Homebridge to apply new config. 
- Notice that object sensors for cameras may or may not show up. 

**Logs:**
<!-- In order to be helpful, include the relevant logs from Homebridge, if applicable. -->

```
[14/09/2021, 16:14:02] [HB Supervisor] Homebridge Process Ended. Code: 143, Signal: null
[14/09/2021, 16:14:07] [HB Supervisor] Restarting Homebridge...
[14/09/2021, 16:14:07] [HB Supervisor] Starting Homebridge with extra flags: -I
[14/09/2021, 16:14:07] [HB Supervisor] Started Homebridge v1.3.4 with PID: 2517
Initializing HAP-NodeJS v0.9.4...
[14/09/2021, 16:14:08] Loaded config.json with 0 accessories and 2 platforms.
[14/09/2021, 16:14:08] Loaded 2 cached accessories from cachedAccessories.
[14/09/2021, 16:14:08] ---
[14/09/2021, 16:14:08] Loaded plugin: homebridge-config-ui-x@4.41.2
[14/09/2021, 16:14:08] Registering platform 'homebridge-config-ui-x.config'
[14/09/2021, 16:14:08] ---
[14/09/2021, 16:14:09] Loaded plugin: homebridge-unifi-protect@4.4.3
[14/09/2021, 16:14:09] Registering platform 'homebridge-unifi-protect.UniFi Protect'
[14/09/2021, 16:14:09] ---
[14/09/2021, 16:14:09] Loading 2 platforms...
[14/09/2021, 16:14:09] [Config] Initializing config platform...
[14/09/2021, 16:14:09] [Config] Running in Service Mode
[14/09/2021, 16:14:09] [UniFi Protect] Initializing UniFi Protect platform...
Preparing Advertiser for 'Homebridge 4CDF 8C7A' using bonjour-hap backend!
Setup Payload:
X-HM://002470MXKZEY5
Enter this code with your HomeKit app on your iOS device to pair with Homebridge:
Starting to advertise 'Homebridge 4CDF 8C7A' using bonjour-hap backend!
[14/09/2021, 16:14:09] Homebridge v1.3.4 (Homebridge 4CDF) is running on port 51849.
[14/09/2021, 16:14:09] [UniFi Protect] UNVR [UNVR4]: Connected to the Protect controller API (address:XX.XX.XX.XXX mac: ).
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4]: Connected to the UniFi realtime update events API.
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Front Doorbell [UVC G4 Doorbell] (address: 192.168.50.20 mac: XXXXXXXXX).
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Carport [UVC G4 Pro] (address: 192.168.50.21 mac: XXXXXXXXXX).
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4]: Controller refresh interval set to 10 seconds.
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4] Front Doorbell [UVC G4 Doorbell]: Discovered doorbell message switch: LEAVE PACKAGE AT DOOR.
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4] Front Doorbell [UVC G4 Doorbell]: Discovered doorbell message switch: DO NOT DISTURB.
[14/09/2021, 16:14:10] [UniFi Protect] UNVR [UNVR4] Front Doorbell [UVC G4 Doorbell]: Discovered doorbell message switch (60 seconds): Coming to the door.
```

**Homebridge Configuration:**

```json
{
    "bridge": {
        "name": "Homebridge 4CDF",
        "username": "XX:XX:XX:XX:XX",
        "port": 51849,
        "pin": "XXX-XX-XXXX"
    },
    "accessories": [],
    "platforms": [
        {
            "name": "Config",
            "port": 8581,
            "platform": "config"
        },
        {
            "controllers": [
                {
                    "address": "XXX.XXX.XX.XXX",
                    "doorbellMessages": [
                        {
                            "message": "Coming to the door"
                        }
                    ],
                    "name": "UNVR",
                    "password": "some_pass",
                    "username": "some_user"
                }
            ],
            "options": [
                "Enable.Motion.SmartDetect",
                "Enable.Motion.SmartDetect.ObjectSensors"
            ],
            "platform": "UniFi Protect"
        }
    ]
}
```

**Screenshots:**
(Shown below without object sensors added. As of writing, I couldn't get one to occur with some/all of the object sensors added.)
![Screen Shot 2021-09-14 at 4 19 19 PM](https://user-images.githubusercontent.com/8331077/133328062-a902ad83-f988-4da3-9ad2-ef42b30a4b34.png)

**Environment:**

* **Homebridge Version:** 1.3.4
* **Node Version:** 14.17.0 -> Updated to 14.17.6, same result.
* **Homebridge-UniFi-Protect Plugin Version:** 4.4.3
* **UniFi Protect Version:** 1.19.0
* **UniFi Protect Controller Type:** UNVR
* **UniFi Protect Controller Firmware Version:** 2.2.7
* **Apple Device and iOS / macOS / iPadOS / tvOS Version:** MacOS 11.5.2 used for config
* **Operating System and OS Version:**  Raspbian

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