getPreferenceControllers() -> createPreferenceControllers() for the same
reason as in ag/3647936
Bug: 73668763
Test: robotests
Change-Id: I97670a91a2a38d1c844d1b9d37f4222c5e6f45a0
After ag/2573096, the batterystats will be refreshed after each
broadcastReceiver registeration. And this registeration happens
in onResume().
So we don't need to init batterystats in onCreate() anymore.
Bug: 65629008
Test: RunSettingsRoboTests
Change-Id: I4ed2d420c6f2bb77d726dac4dd58fa6704ce6929