Fix issues in battery usage accounting

1. In High usage dialog, show top apps based on battery usage, not app
time.
2. Refactor the check for hidden system modules into ShouldHideSipper,
however don't smear it, this is also the current logic before this CL.

Bug: 133445008
Test: RunSettingsRoboTests
Change-Id: I851a1c9ef9b79a934ba0501cd96001f2e450bda4