* Use native video call picture in picture!
* Handle isSupported, isPossible and web view errors.
* Use new canEnterPip method.
* Hide a room's Call button when already joined to the call.
* Tweak feature flag description.
* PR comments.
- we're currently working around the widget not properly aquiring media streams by manually terminating a call before starting the web view
- it seems that there's a race condition between that and the system opening the app
- as such we need to delay terminating the call until the system gets a chance to handle the redirect
- CallKit decides what action to to take when pressing the hardware lock button based on where the audio is routed to. Using the speaker will make it lock the phone while using the headset will make it end the call.
- Before the introduction of CallKit we had to manually setup the AudioSession to keep the audio live in the background. This is now clashing with CallKit making it bevelie the audio is not routed to the speaker and causing the call be terminated when pressing the lock button.
- not completely sure why this happens but `reportOutgoingCall` interferes with how the WebView gets access to video streams
- the call itself isn't really necessary so removing it is the simplest way forward
- tear down ElementCall screens when ending the call from the CXCallController
- make the call UI available in the task manager and lock screen
- Fix broken hang up widget message format
