AVFAudio tvOS xcode13.0 beta5

#AVFAudio.framework https://github.com/xamarin/xamarin-macios/pull/12550

diff -ruN /Applications/Xcode_13.0.0-beta4.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/AVFAudio.framework/Headers/AVAudioSession.h /Applications/Xcode_13.0.0-beta5.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/AVFAudio.framework/Headers/AVAudioSession.h
--- /Applications/Xcode_13.0.0-beta4.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/AVFAudio.framework/Headers/AVAudioSession.h	2021-07-23 13:30:55.000000000 -0400
+++ /Applications/Xcode_13.0.0-beta5.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/AVFAudio.framework/Headers/AVAudioSession.h	2021-08-09 03:22:53.000000000 -0400
@@ -185,7 +185,13 @@
  
 	Note that activating an audio session is a synchronous (blocking) operation.
 	Therefore, we recommend that applications not activate their session from a thread where a long
-	blocking operation will be problematic. When deactivating a session, the caller is required to
+	blocking operation will be problematic.
+	Apps may activate a AVAudioSessionCategoryPlayback session when another app is hosting a
+	call (to start a SharePlay activity for example). However, they are not permitted to capture the
+    microphone of the active call, so attempts to activate a session with category
+	AVAudioSessionCategoryRecord or AVAudioSessionCategoryPlayAndRecord will fail with error
+	AVAudioSessionErrorCodeInsufficientPriority.
+	When deactivating a session, the caller is required to
 	first stop or pause all running I/Os (e.g. audio queues, players, recorders, converters,
 	remote I/Os, etc.). Starting in iOS 8, if the session has running I/Os at the time that
 	deactivation is requested, the session will be deactivated, but the method will return NO and