Changing the system theme no longer causes a UMO flicker

Recreating the UMO causes a visual flicker. Since the
theme can be changed from a quick setting, this flicker
may occur while it is onscreen. The UMO now uses it's
own colors and does not need to be recreated for theme
changes.

Test: Manual
Fixes: 232295658
Fixes: 204414378
Change-Id: Ifcdb95e7b783cfe8634c8280ac1aa13f193e04bd