Merge "Implement pressing back button and swiping back" into sc-v2-dev am: 97d749833c am: 1cfa05ad08

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/16013509

Change-Id: I087ff9a5482c88f9034b1c51227d73c2412c89c7