Clear refs to the controller and saved snapshot upon finishing animation

Bug: 79322746
Change-Id: I8786909615da3368a22300d5e33cefa4b77623fd

quickstep/src/com/android/quickstep/RecentsAnimationWrapper.java

@@ -58,6 +58,7 @@ public class RecentsAnimationWrapper {
                     if (onFinishComplete != null) {
                         onFinishComplete.run();
                     }
+                    controller = null;
                 }
             }
         });

quickstep/src/com/android/quickstep/WindowTransformSwipeHandler.java

@@ -677,6 +677,7 @@ public class WindowTransformSwipeHandler<T extends BaseDraggingActivity> {
 
         mActivityInitListener.unregister();
         mInputConsumer.unregisterInputConsumer();
+        mTaskSnapshot = null;
     }
 
     private void invalidateHandlerWithLauncher() {