Limit ambient aod to supported devices

Ambient AOD (visible wallpapers) will only be supported by
particular displays. Use config to control which devices this
is enabled for. Also simplify the logic used to determine
when the ambient wallpaper is supported.

Test: atest WallpaperRepositoryImplTest
Flag: com.android.systemui.shared.ambient_aod
Bug: 373844670
Change-Id: I17aace2eff74bfd9be6f17944cae988723fdda78