How Can we disable Camera and Microphone for xamarin webview?

I deleted permissions camera and audio from manifest file, and added:

<uses-feature android:name="android.hardware.microphone" android:required="false" />
<uses-feature android:name="android.hardware.camera" android:required="false" />
<uses-feature android:name="android.hardware.camera2" android:required="false" />

but when I loading page https://browserleaks.com/webrtc or https://pixelscan.net I see, that wertc still working