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

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

Change-Id: Ie7ef15d18fe3b4f03f5171bafd1d59058c916429