Use splashscreen if we can't fill horizontaly with snapshot

A gap at the right side of the snapshot looks pretty bad. Thus,
we use a splash screen in case there would be a gap on the right
side. However, we don't want to do this from recents as we'd
produce another flicker

Test: go/wm-smoke
Test: Open app portrait, go launcher, rotate, open app landscape
Test: Open app landscape, go launcher rotate, open app portrait
Fixes: 62094756
Change-Id: Iaf1fecced822685187477a4698fa6b67c6e485d7