Remove scheduling animation which is no longer needed

Bug: 63914027
Test: android.server.wm.CrossAppDragAndDropTests, manually check the
      rejected animation and the cancel animation.
Change-Id: I6bdce7fb406fa8ae622d634fa224c993b078bf8a

services/core/java/com/android/server/wm/DragState.java

@@ -412,7 +412,6 @@ class DragState {
         }
         if (!mDragResult) {
             mAnimator = createReturnAnimationLocked();
-            mService.scheduleAnimationLocked();
             return;  // Will call cleanUpDragLw when the animation is done.
         }
         cleanUpDragLw();