TV:Fade out PiP content during aspect ratio change

This avoids stretching the content - the content will only be shown
again once it has been redrawn by the app for the new ratio.

Content should stay visible during the enter and move animation, i.e.
whenever the ratio stays the same.

Bug: 230741005
Test: manual - enter PiP, change aspect ratio, expand, move

Change-Id: Ie95f4a480a622c7403f342e0ac25660fd2af197f