[Catalyst] Avoid PreferenceAvailabilityProvider for ambient wallpaper

The availability is effectively constant on the device. Move the
condition check to hierarchy, which improves settings search.

NO_IFTTT=Catalyst only

Bug: 396630828
Flag: com.android.systemui.shared.ambient_aod
Test: manual
Change-Id: I1141796b73d637dce4fcaf79f026636bd353990f