Apply Dark theme changes when screen off only

this change waits to apply ui changes after screen off
battery manager sends updates and continuously updates the ui mode

this change also applies external changes to ui configurations when
the mode is actually changed. this resolves some perfromance regression
issues

Fixes: 145694649
Fixes: 145161355
Fixes: 145776479

Test: atest UiModeManagerService
Change-Id: Ib769df4302d1c09166e2dc456b8ced35daa4d0b7
Merged-In: Ib769df4302d1c09166e2dc456b8ced35daa4d0b7