Move robolectric tests from 3.6.2 to 4.8.2 am: bc4cc094c7

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

Change-Id: I85283e88e240acc2fc1b37ca0adb7f3a35535a2a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>