Crashes HB
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**Describe The Problem:**
Crashes homebridge



**To Reproduce:**

homebridge-unifi-protect v5.5.0
Unifi protect 1.21.2



**Logs:**

```php
[2/24/2022, 3:31:14 PM] TypeError: Cannot read properties of undefined (reading 'hksv')
    at WebSocket.nvrApi.eventsWs.on.updatesListener (/homebridge/node_modules/homebridge-unifi-protect/src/protect-nvr-events.ts:246:37)
    at WebSocket.emit (node:events:520:28)
    at Receiver.receiverOnMessage (/homebridge/node_modules/homebridge-unifi-protect/node_modules/ws/lib/websocket.js:1137:20)
    at Receiver.emit (node:events:520:28)
    at Receiver.dataMessage (/homebridge/node_modules/homebridge-unifi-protect/node_modules/ws/lib/receiver.js:513:14)
    at Receiver.getData (/homebridge/node_modules/homebridge-unifi-protect/node_modules/ws/lib/receiver.js:446:17)
    at Receiver.startLoop (/homebridge/node_modules/homebridge-unifi-protect/node_modules/ws/lib/receiver.js:148:22)
    at Receiver._write (/homebridge/node_modules/homebridge-unifi-protect/node_modules/ws/lib/receiver.js:83:10)
    at writeOrBuffer (node:internal/streams/writable:389:12)
    at _write (node:internal/streams/writable:330:10)
[2/24/2022, 3:31:14 PM] Got SIGTERM, shutting down Homebridge...
```
**Homebridge Configuration:**

not much 
```json

        {
            "controllers": [
                {
                    "address": "192.168.100.3",
                    "password": "*****",
                    "username": "SVC_homebridge"
                }
            ],
            "verboseFfmpeg": true,
            "platform": "UniFi Protect"
        },
```

**Screenshots:**
![Screen Shot 2022-02-24 at 3 50 38 PM](https://user-images.githubusercontent.com/807787/155613636-f1bdc290-a251-4ab4-83c7-82aaf90ad856.png)
**Environment:**

* **Homebridge Version:** 1.4.0
* **Node Version:** 16.14.0
* **Homebridge-UniFi-Protect Plugin Version:**
* **UniFi Protect Version:** 1.21.2
* **UniFi Protect Controller Type:**CKII

* **Operating System and OS Version:** <!-- Raspbian / docker

