Merge "AssistContentRequester-weaken references to system callback" into sc-dev am: 7d54a31ba9 am: 657d795b88 am: f599118c23

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14413471

Change-Id: Ibf1c4ca6d7771638cdf57113160969c8d431b936