Fix crash/flicker with taskbar when canceling drag and drop

The surfaceControl transaction is performed more than once so close
the transaction at the end of the animation.

Test: manual - start a drag from taskbar into split and then pull it
               back so that it doesn't complete
             => ensure taskbar doesn't flicker / no crash in logs
Bug: 228006271
Change-Id: I38c8efe310596bbbbf09f361c266a7fefc1b2eea

quickstep/src/com/android/launcher3/taskbar/TaskbarDragController.java

@@ -477,7 +477,6 @@ public class TaskbarDragController extends DragController<BaseTaskbarContext> im
                 tx.setScale(dragSurface, scale, scale);
                 tx.setAlpha(dragSurface, alpha);
                 tx.apply();
-                tx.close();
             }
         });
         mReturnAnimator.addListener(new AnimatorListenerAdapter() {
@@ -498,6 +497,7 @@ public class TaskbarDragController extends DragController<BaseTaskbarContext> im
             }
 
             private void cleanUpSurface() {
+                tx.close();
                 maybeOnDragEnd();
                 // Synchronize removing the drag surface with the next draw after calling
                 // maybeOnDragEnd()
@@ -508,7 +508,6 @@ public class TaskbarDragController extends DragController<BaseTaskbarContext> im
                 syncer.addToSync(syncId, viewRoot.getView());
                 syncer.addTransactionToSync(syncId, transaction);
                 syncer.markSyncReady(syncId);
-
                 mReturnAnimator = null;
             }
         });