Adds modern wallpaper pickers to AOSP installs

Bug: b/294871815
Test: built and flashed aosp device and launched ThemePicker
Change-Id: I2658d2e5b4d4500f5a991c049f3ea9d2eb2db1a8
Merged-In: I2658d2e5b4d4500f5a991c049f3ea9d2eb2db1a8
Test: ran all CTS tests per b/294871815#comment11 on aosp device with ThemePicker
Ignore-AOSP-First: Change only applies to udc-qpr-dev and forward and will cause breakages in tm-dev and udc-dev.