Ensure the deferred callback does not finish next animation

This fixes the timing that another animation is starting and the
previous deferred onFinished callback is invoked after that. It
will cause the next animation to use the released leash and then
crashes in onAnimationStart or onAnimationUpdate.

Bug: 124303221
Test: atest SurfaceAnimatorTest#testDeferFinishDoNotFinishNextAnimation

Change-Id: Ia04b8433ed6f9a9d88295b4986a5063c2271ca80