Fix audio preview muting game audio indefinitely when beatmap p… (#6738)

Fix audio preview muting game audio indefinitely when beatmap panel is off-screen

Co-authored-by: Dan Balasescu <smoogipoo@smgi.me>

osu.Game/Audio/PreviewTrack.cs

@@ -13,11 +13,13 @@ namespace osu.Game.Audio
     {
         /// <summary>
         /// Invoked when this <see cref="PreviewTrack"/> has stopped playing.
+        /// Not invoked in a thread-safe context.
         /// </summary>
         public event Action Stopped;
 
         /// <summary>
         /// Invoked when this <see cref="PreviewTrack"/> has started playing.
+        /// Not invoked in a thread-safe context.
         /// </summary>
         public event Action Started;
 
@@ -29,7 +31,7 @@ namespace osu.Game.Audio
         {
             track = GetTrack();
             if (track != null)
-                track.Completed += () => Schedule(Stop);
+                track.Completed += Stop;
         }
 
         /// <summary>
@@ -93,6 +95,7 @@ namespace osu.Game.Audio
             hasStarted = false;
 
             track.Stop();
+
             Stopped?.Invoke();
         }
 

osu.Game/Audio/PreviewTrackManager.cs

@@ -46,18 +46,18 @@ namespace osu.Game.Audio
         {
             var track = CreatePreviewTrack(beatmapSetInfo, trackStore);
 
-            track.Started += () =>
+            track.Started += () => Schedule(() =>
             {
                 current?.Stop();
                 current = track;
                 audio.Tracks.AddAdjustment(AdjustableProperty.Volume, muteBindable);
-            };
+            });
 
-            track.Stopped += () =>
+            track.Stopped += () => Schedule(() =>
             {
                 current = null;
                 audio.Tracks.RemoveAdjustment(AdjustableProperty.Volume, muteBindable);
-            };
+            });
 
             return track;
         }