fix close external clients

Azaion.Annotator/Annotator.xaml.cs

@@ -395,6 +395,7 @@ public partial class Annotator
         MainCancellationSource.Cancel();
         _inferenceService.StopInference();
         DetectionCancellationSource.Cancel();
+
         _mediaPlayer.Stop();
         _mediaPlayer.Dispose();
         _libVLC.Dispose();