Use color overlay for fixed rotation in btn nav

Use color overlay instead of app icon overlay with fixed rotation
on in button navigation mode. This is a temporary workaround
to avoid app icon squashing due to animator issue in btn nav
with non zero rotation.

Before: http://recall/-/da2uuq57YtQRpR4N9NryZR/dFiyWX27i9rEPm3VTvj4Or
After: http://recall/-/da2uuq57YtQRpR4N9NryZR/gUl5wasVU7z8B9JKQYpWRk

Bug: 319286295
Test: manually enter PiP w/ fixed rotation in btn nav and srcRectHint=null
Change-Id: Id7c8da71714bc34dd4a9b679c96b6b32d6bac6de