Fix prefab Script track remapping in scene animations

Store prefab object IDs for Script tracks authored from prefab objects and mark those tracks as prefab object references so SceneAnimationPlayer can remap them for prefab instances.

Source/Editor/GUI/Timeline/Tracks/ScriptTrack.cs

@@ -52,8 +52,67 @@ namespace FlaxEditor.GUI.Timeline.Tracks
         /// </summary>
         public Script Script
         {
-            get => FlaxEngine.Object.TryFind<Script>(ref ScriptID);
-            set => ScriptID = value?.ID ?? Guid.Empty;
+            get
+            {
+                if (Flags.HasFlag(TrackFlags.PrefabObject))
+                {
+                    // TODO: reuse cached script to improve perf
+                    foreach (var window in Editor.Instance.Windows.Windows)
+                    {
+                        if (window is Windows.Assets.PrefabWindow prefabWindow && prefabWindow.Graph.MainActor)
+                        {
+                            var script = FindScriptWithPrefabObjectID(prefabWindow.Graph.MainActor, ref ScriptID);
+                            if (script != null)
+                                return script;
+                        }
+                    }
+                    return null;
+                }
+                return FlaxEngine.Object.TryFind<Script>(ref ScriptID);
+            }
+            set
+            {
+                if (value != null)
+                {
+                    if (value.HasPrefabLink && !value.HasScene)
+                    {
+                        // Track with prefab object reference assigned in Editor
+                        ScriptID = value.PrefabObjectID;
+                        Flags |= TrackFlags.PrefabObject;
+                    }
+                    else
+                    {
+                        ScriptID = value.ID;
+                        Flags &= ~TrackFlags.PrefabObject;
+                    }
+                }
+                else
+                {
+                    ScriptID = Guid.Empty;
+                    Flags &= ~TrackFlags.PrefabObject;
+                }
+            }
+        }
+
+        private static Script FindScriptWithPrefabObjectID(Actor actor, ref Guid id)
+        {
+            if (actor == null)
+                return null;
+
+            var scripts = actor.Scripts;
+            for (int i = 0; i < scripts.Length; i++)
+            {
+                var script = scripts[i];
+                if (script && script.PrefabObjectID == id)
+                    return script;
+            }
+            for (int i = 0; i < actor.ChildrenCount; i++)
+            {
+                var e = FindScriptWithPrefabObjectID(actor.GetChild(i), ref id);
+                if (e != null)
+                    return e;
+            }
+            return null;
         }
 
         /// <inheritdoc />