Merge "When KEYCODE_BACK is received, hide keyboard" into sc-dev am: 24c8ebd88d am: 37af2c5bd8

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15107283

Change-Id: I37ec91a70eced62ac96ab5b9f3f9c15b9cd79d94