Not to retrieve Preference_title

No longer retrieve Preference_title in SettingsMainSwitchPreference,
because it's private in androidx, migrate to Preference's getTitle() and
setTitle() instead.

This will help to fix references to resources for Settings in the future
cls.

Bug: 293810334
Test: visual - on Adaptive brightness page
Change-Id: If40a879ff222e980a563662797dffb00f6b62597