Merge "Provide the back callback instance when unregistering it from SysUI."...

Merge "Provide the back callback instance when unregistering it from SysUI." into tm-dev am: eba6a95a am: ada82e18

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/17650016



Change-Id: I648b5edad46ee743e0ebe06ed174be7fac53cf34
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>