No audio from Nest cameras when viewed in Homekit
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**Describe the bug**
No audio present when viewing the cameras in HomeKit. Occuring with 3 cameras. 

**Debug Output**
running latest Homekit and plug in versions (with updates)
**To Reproduce**

Steps to reproduce the behavior:

1. N/A

**Expected behavior**

N//A

Please answer these questions before submitting this issue:
```
On what device are you running homebridge: Raspberry Pi 4 Model B (8GB)

On what iOS version are you having issues:  iOS 14.1, iPadOS 14.1, MacOS 10.15.7

What camera types are having issues: 2 Nest Cams and 1 Dropbox (pre-nest acquisition)

Does this issue occur consistently or randomly: Consistently no audio. Audio has never played.
