Move robolectric tests from 3.6.2 to 4.8.2 am: 709b39831d

Original change: https://android-review.googlesource.com/c/platform/packages/apps/WallpaperPicker2/+/2292133

Change-Id: I3b90409c4271d082309c906a396315807da76474
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>