Merge "Add a background scrim to launcher for text protection." into sc-dev am: f1d3cf02c9 am: 232fadabb8

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14243130

Change-Id: I777fb7d4a4cc2557c225a8829efb6f6b15b89c5a