Merge "Add ENABLE_SCRIM_FOR_APP_LAUNCH feature flag." into sc-dev am: 28e39335bc am: 95168f389e

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14987185

Change-Id: I85c35932622f001fac00a9f0031b2d00bbcf674e