[Catalyst] Add PreferenceIndexableProvider

Bug: 441444345
Flag: com.android.settings.flags.catalyst_settings_search
Test: adb shell content query --uri content://com.android.settings/settings/indexables_raw | grep CS:
Test: adb shell content query --uri content://com.android.settings/settings/dynamic_indexables_raw | grep CS:
Change-Id: Ia9a9293f85bc89faa4282c7f463313c721de3fa7