Activity.isAnimating reports window animations

isAnimating() should return true for any kind of animation considered
byt the activity. Window animations are triggered when a floating
activity resizes itself or gets pushed around by an inset.

Bug: 226453118
Test: atest CtsWindowManagerDeviceTestCases:MoveAnimationTests
Change-Id: I3293c22b9cec479c329c996d71e022a8f5ca76a1