Add warning message when power save mode is enabled for attention settings fragment

Test: locally with flame, make RunSettingsRoboTests -j96 ROBOTEST_FILTER=AdaptiveSleepPreferenceControllerTest,AdaptiveSleepBatterySaverPreferenceControllerTest

Bug: 186690152
Change-Id: I42e018a8cf48166a8250fac9510a8882efb58568
5 files changed