Remove the legacy smart battery tip from the battery settings, which
will remind users to eanble the "adaptive battery" if users disable it.
Reasons: 1) 98% users will always keep the AB is enabled, and 2) we move
the AB into the battery saver page, there is no individual page anymore
Fix: 281798483
Test: make test RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.fuelgauge.batterytip.*
Change-Id: I85739b88ee9373b95a62271d2eb0137cf411d8cb
2f42eb20f3