Two way audio not working in HomeKit
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**Describe The Problem:**

Hi there, 

two way audio does not seem to work for me in HomeKit. I'm testing with an UVC G3 Instant. If I try it from the Protect mobile app, I first hear a sound from the camera and after that I can speak without any problems. Trying the same in HomeKit does neither cause the camera to play the initial sound nor can I hear my voice.

**To Reproduce:**

In HomeKit, select the camera, press "speak" and say a few words.

**Logs:**

Nothing related in the output/logs (default verbosity).

**Homebridge Configuration:**

Standard config with a single UNVR. I created a dedicated Homebridge user on my UNVR and assigned the "view only" role. As well tried after additionally assigning the "administrator" role, without any noticeable change.

**Screenshots:**
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**Environment:**

* **Homebridge Version:** <!-- homebridge -V -->
* **Node Version:** v14.17.6
* **Homebridge-UniFi-Protect Plugin Version:** v4.4.3
* **UniFi Protect Version:** 1.19.0
* **UniFi Protect Controller Type:** UNVR
* **UniFi Protect Controller Firmware Version:** 2.2.7
* **Apple Device and iOS / macOS / iPadOS / tvOS Version:** iOS 15 on iPhone XS Max
* **Operating System and OS Version:** Windows 10
