Enable two-part fade on TV icon splash screens

The splash screen exit animation reveals the content of the app.
If the splash screen shows an icon, this CL changes the exit animation such that the icon fades out first and then the splash screen window is faded out. This prevents the icon overlapping with the app content, which doesn't look good

Bug: 296354973
Test: manual
Change-Id: I20cc0745c2f5f8dd6e21d3654110b9eca543b80c