Move robolectric tests from 3.6.2 to 4.8.2 am: bc4cc094c7 am: 076c3c4581

Original change: https://android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/2292054

Change-Id: I6e3377b4b6a1a1c4b0359a062cc143f8a07a1ef9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>