Convert RTCVideoView stateful widget to stateless one
Convert RTCVideoView stateful widget to stateless one

flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc,flutter-webrtc/flutter-webrtc