Revert^2 "BC25 Preview current wallpapers (2/2)"

Original change ag/28168949 caused post-submit build failures. Bringing
the original change back with fixes in WPPG to resolve test failures,
verified using ABTD.

Flag: com.android.wallpaper.new_picker_ui_flag
Bug: 348462236
Test: tested on ABTD to ensure the original build error is resolved
Change-Id: Ib1048d32667a665b41a94ed45ef3f35098147b1f