Do not allow home screen only wallpaper if current is the default am: 7742666ea7 am: cd23f3d5f0 am: 9e756db176 am: c1d3e9691f

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/WallpaperPicker2/+/15567276

Change-Id: I78f727b4429196f4f61c79dd1daa3fb576b430ef