 data URL / base64 snapshot corrupted
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**Describe The Problem:**
<!-- A clear and concise description of what the issue is. -->

My attempts to decode the base64 string from my Unifi Doorbell are unsuccessful.

This is the image that I decode from the data URL:

![convertedFile](https://user-images.githubusercontent.com/52816569/117545411-f4118700-b025-11eb-8240-75399c78cabf.jpg)

I can see the beginning of the watermark but then the image just get corrupted. 

**To Reproduce:**
send an MQTT message `true` to `unifi/protect/[MAC]/snapshot/trigger`

receive the following response:
```
data:image/jpeg;base64,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...
```

I have the feeling that the data URL got truncated. Maybe its too large to fit inside an MQTT payload...

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

```
[5/8/2021, 6:02:11 PM] [UniFi Protect] UniFi-CloudKey-Gen2-Plus [UCK-G2-PLUS] Entrée Oest [UVC G4 Doorbell]: Snapshot triggered via MQTT.
```

**Homebridge Configuration:**

```json
Show the relevant portion of your homebridge config.json here, if needed.
Remove any sensitive information.
```

**Screenshots:**
<!-- If applicable, add screenshots to help explain your problem. -->

**Environment:**

* **Homebridge Version:** v1.3.4
* **Node Version:** v14.16.0
* **Homebridge-UniFi-Protect Plugin Version:** v4.4.0
* **UniFi Protect Version:** 1.18.0
* **UniFi Protect Controller Type:** UCKgen2+
* **UniFi Protect Controller Firmware Version:** 2.1.7
* **Apple Device and iOS / macOS / iPadOS / tvOS Version:** iOS 14.5.1 iPhone 12 Pro Max ; macOS 11.3.1 MacBookPro 13,3 
* **Operating System and OS Version:** RockPro64 armbian buster Docker

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