AOSP/WallpaperPicker - update the WallpaperPicker test package version to target P (28) or higher. am: f147ac2fdb am: b50b0d2d71 am: 7e4e26fee6 am: 4fd92c6175 am: 26df17875a am: b6eff2dff2 am: 8284057853 am: c637e7efb8

Original change: https://android-review.googlesource.com/c/platform/packages/apps/WallpaperPicker/+/849112

Change-Id: Ic55707da21a42b1ffc3bb32dd90a977683c92ee7
Signed-off-by: Automerger Merge Worker <[email protected]>