Inconsistent behavior on doorbell trigger
**Describe The Problem:**
I enabled the doorbell trigger ("Enable.Doorbell.Trigger"), so I can have it trigger external chimes, as well as automatically set a message on the doorbell display.

However, although Homekit registers every time the doorbell button is pushed and pops up a message that someone pressed the doorbell, the actual doorbell trigger accessory only triggers once in a while, making the whole setup very unreliable.

As I also integrate Homekit in to my Domoticz, I can tell that the trigger hasn't been registered there a single time since the 21st of this month, even though I have just been testing, and pressed the doorbell 3 times in a row!

**To Reproduce:**
Enable "Enable.Doorbell.Trigger" and restart, then press doorbell button and observe trigger NOT switching

**Logs:**
```[9/27/2021, 6:55:55 PM] [Ring] Found the following locations:
[9/27/2021, 6:55:55 PM] [Ring]   locationId: 376ff...791 - My Location
[9/27/2021, 6:55:56 PM] [Ring] Configuring 1 cameras and 5 devices for location "My Location" - locationId: 376ff...791
[9/27/2021, 6:56:36 PM] [Homebridge UI] [admin] Accessory layout changes saved.
[9/27/2021, 6:56:39 PM] [Homebridge UI] [admin] Accessory layout changes saved.
[9/27/2021, 6:56:49 PM] [Homebridge UI] [admin] Accessory layout changes saved.
[9/27/2021, 6:57:15 PM] [UniFi Protect] Fam Peeters UniFi Controller [UCK-G2-PLUS] Deurbel [UVC G4 Doorbell]: Streaming request from 1.2.3.5: 320x240@15fps, 68 kbps. Using RTSP stream profile: 480x360@30fps (Low), 200 kbps.
[9/27/2021, 6:57:17 PM] [UniFi Protect] Fam Peeters UniFi Controller [UCK-G2-PLUS] Deurbel [UVC G4 Doorbell]: Stopped video streaming session.
[9/27/2021, 6:57:54 PM] [Homebridge UI] [admin] Accessory layout changes saved.
[9/27/2021, 6:58:02 PM] [Homebridge UI] [admin] Accessory layout changes saved.
[9/27/2021, 7:23:08 PM] [UniFi Protect] Fam Peeters UniFi Controller [UCK-G2-PLUS] Deurbel [UVC G4 Doorbell]: Streaming request from 1.2.3.5: 320x240@15fps, 68 kbps. Using RTSP stream profile: 480x360@30fps (Low), 200 kbps.
```

**Homebridge Configuration:**

```json
{
    "platform": "UniFi Protect",
    "options": [
        "Enable.Doorbell.Trigger",
        "Enable.Motion.SmartDetect"
    ],
    "controllers": [
        {
            "address": "1.2.3.4",
            "doorbellMessages": [
                {
                    "duration": 60,
                    "message": "Even geduld, er komt iemand!"
                },
                {
                    "duration": 0,
                    "message": "GEEN VERKOOP E.D. aan de deur!"
                },
                {
                    "duration": 1440,
                    "message": "We zitten achter! Loop even om"
                }
            ],
            "mqttTopic": "unifi/protect",
            "mqttUrl": "mqtt://a:b@1.2.3.4:1883",
            "password": "password",
            "username": "user"
        }
    ]
}
```

**Screenshots:**
N/A

**Environment:**

* **Homebridge Version:** v1.3.4 
* **Node Version:** v14.17.6 
* **Homebridge-UniFi-Protect Plugin Version:** v4.3.3
* **UniFi Protect Version:** v1.19.2
* **UniFi Protect Controller Type:** UCKgen2+
* **UniFi Protect Controller Firmware Version:** v2.1.11
* **Apple Device and iOS / macOS / iPadOS / tvOS Version:** iPad 7th gen on iPadOS v14.7.1
* **Operating System and OS Version:** Ubuntu 20.04


