Show app list in Battery Usage page when there is no battery level data.

https://drive.google.com/file/d/1iQxKmEp_weNYdT4JnsiZgYy9mCdn7SRv/view?usp=sharing

Bug: 246233366
Test: make RunSettingsRoboTests + manually
Change-Id: If536c93652506c8009f5cabf3d0ae373b6825bfc
Merged-In: If536c93652506c8009f5cabf3d0ae373b6825bfc