fix dart pub publish --dry-run.

Author: cloudwebrtc

lib/src/track/processor.dart

@@ -1,4 +1,4 @@
-import 'package:webrtc_interface/webrtc_interface.dart';
+import 'package:flutter_webrtc/flutter_webrtc.dart';
 
 import '../core/room.dart';
 import '../types/other.dart';

lib/src/track/track.dart

@@ -141,6 +141,7 @@ abstract class Track extends DisposableChangeNotifier
 
     if (_originalTrack != null) {
       await _originalTrack?.stop();
+      _originalTrack = null;
     }
 
     _active = false;