Fix test breakage in settingslib

If we bump up the API level to 26 in settingslib robo tests,
BatteryMeterDrawableBaseTest has test failure.

This cl fix it by inject to the critical level and bump up API
level.

Bug: 69001622
Test: RunSettingsLibRoboTests
Change-Id: I1b70d9ac23be000efbaed3edcef912e6787ebc5c