Merge "Fade out empty Overview message." into sc-dev am: 13e4618b57 am: e471fbf3a4

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14415793

Change-Id: I8d89685c3b2e91c4d328b5c2ae6930352b32b042