Fix HUN launch animation.

This CL fixes HUN launch animation by making sure that the HUN is hidden
only when the launch animation is ended, cancelled, aborted or timed
out.

See b/186389197#comment2 for before/after videos.

Bug: 186389197
Test: Click a HUN notification
Test: atest ActivityLaunchAnimatorTest
Change-Id: I3c8e1d8195124946aef5a25c411b6913157179b8