chore(brightness suw): adjust auto brightness detail page footer content description

Ref to the bug, s2s and talkback pages' footer content descriptions are
prefixed with "About XXX" for talkbalk info announcement. Therefore, for
auto brightness detail page in SUW, we also prefix "About adaptive
brightness" to the footer preference content description, to improve
the consistency with other accessiblity feature suw pages.

Bug: 347859318
Flag: com.android.settings.accessibility.add_brightness_settings_in_suw
Test: manually
      atest AutoBrightnessPreferenceFragmentForSetupWizardTest
Change-Id: Ieda4bcffb4f4e11ea68c961beee5c2fff1b29f2c