Fixed pulsing notifications and flickers with the scrim

When the scrim required blanking, the behavior wasn't working
as expected anymore since we would now call onFinished immediately
instead of when the animation has actually finished. Additionally
was the onDisplayBlanked() then dropped since we already finished
before.

Fixes: 143185828
Fixes: 143195895
Test: atest SystemUITests
Change-Id: Iccc303065b4cf4ff2601b10b528b82b9a90a8d3e