Plugin fails to start with "Throttling API calls..." error
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**Describe The Problem:**
I have a fresh installation of Homebridge with the homebridge-unifi-protect plugin, and the plugin fails to start with a "Throttling API calls due to errors..." error. No additional info is available in the log. 

**To Reproduce:**
* Installed homebridge using the steps outlined in the documentation.
* Checked available firmware and UniFi Protect updates (everything was up to date).
* Created a local superadmin on UDM-Pro, and enabled all RTSP streams on the single G3 Flex camera I have (verified the streams with VLC).
* Installed homebridge-unifi-protect documentation and set it up with the controller address/local account etc.
* Restarted Homebridge server.

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

```
[1/6/2021, 2:19:18 PM] [HB Supervisor] Restarting Homebridge...
[1/6/2021, 2:19:18 PM] [HB Supervisor] Starting Homebridge with extra flags: -I -D
[1/6/2021, 2:19:18 PM] [HB Supervisor] Started Homebridge v1.1.7 with PID: 2754
[1/6/2021, 2:19:18 PM] Loaded config.json with 0 accessories and 2 platforms.
[1/6/2021, 2:19:18 PM] ---
[1/6/2021, 2:19:18 PM] Loaded plugin: homebridge-config-ui-x@4.36.0
[1/6/2021, 2:19:18 PM] Registering platform 'homebridge-config-ui-x.config'
[1/6/2021, 2:19:18 PM] ---
[1/6/2021, 2:19:18 PM] Loaded plugin: homebridge-unifi-protect@4.3.5
[1/6/2021, 2:19:18 PM] Registering platform 'homebridge-unifi-protect.UniFi Protect'
[1/6/2021, 2:19:18 PM] ---
[1/6/2021, 2:19:18 PM] Loading 2 platforms...
[1/6/2021, 2:19:18 PM] [Config] Initializing config platform...
[1/6/2021, 2:19:18 PM] [Config] Running in Service Mode
[1/6/2021, 2:19:18 PM] [UniFi Protect] Initializing UniFi Protect platform...
Setup Payload:
X-HM://0024JO3XLN3MF
Enter this code with your HomeKit app on your iOS device to pair with Homebridge: <code>
[1/6/2021, 2:19:18 PM] Homebridge is running on port 51424.
[1/6/2021, 2:19:49 PM] [UniFi Protect] 192.168.1.1: Throttling API calls due to errors with the 10 previous attempts. I'll retry again in 5 minutes.
```

**Homebridge Configuration:**

```json
{
    "bridge": {
        "name": "Homebridge 8FC6",
        "username": <username>,
        "port": 51424,
        "pin": <pin>
    },
    "accessories": [],
    "platforms": [
        {
            "name": "Config",
            "port": 8581,
            "auth": "form",
            "theme": "auto",
            "tempUnits": "f",
            "lang": "auto",
            "platform": "config"
        },
        {
            "controllers": [
                {
                    "address": "192.168.1.1",
                    "password": <password>,
                    "username": <username>
                }
            ],
            "verboseFfmpeg": false,
            "platform": "UniFi Protect"
        }
    ]
}
```

**Screenshots:**
N/A

**Environment:**

* **Homebridge Version:** v1.1.7
* **Node Version:** v14.15.4
* **Homebridge-UniFi-Protect Plugin Version:** v4.3.5
* **UniFi Protect Version:** v1.16.9
* **UniFi Protect Controller Type:** UDM-Pro
* **UniFi Protect Controller Firmware Version:** v1.8.5
* **Apple Device and iOS / macOS / iPadOS / tvOS Version:** iPhone 12 Pro Max, iOS 14.3
* **Operating System and OS Version:** Ubuntu Focal Fossa (20.04.1 LTS)

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