Merge "Notify when quickstep gesture starts" into sc-dev am: 1f9fcf87f7 am: be608fe5d7

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14630659

Change-Id: I8850953e98bcefca0c1a265088fcc4907db6e9e1