Merge "Reset activity reference after invalidation" into sc-dev am: f5278b0b23 am: b0e55db99e

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14253506

Change-Id: If33aa1b8d0ddcfa921a76adee9c3e84f52377cd8