Add Foreground Service time to battery usage

Add foreground service time to foreground usage time of apps. This will
account for app usage that user is aware of but is not being displayed
on screen, such as playing music while screen is locked.

Change-Id: Ica9fe0819e46b50299eb2eab7f0483ea01441fb0
Fixes: 38313557
Test: RunSettingsRoboTests