Merge "Update folder preview and folder background colors." into sc-v2-dev am: 273aa1c7af am: 6e7544f0a6

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15998135

Change-Id: I0f688a0eb7e490f97043dd347eb97cb0e5b6654e