Fix window affecting SysUi visibility for once and all

This unforunately introduces another quasi-visibiltiy method but
I think this is the best solution, as the code is pretty clean.

Test: Navigate through, settings, make sure no flickering
Test: Launch music from notification
Test: Launch United app
Test: Go settings -> app -> settings repeadetly 100 times, make
sure light bar transition is always clean
Fixes: 38216281

Change-Id: I0b97334dea3bfef2966ad0c7dd8bbd9907f2574c