Remove @WorkerThread annotation and Preconditions.assertWorkerThread check. am: f781ef81bf

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/23566433

Change-Id: I458ffb6f8ba6d5c5b29f92cd22977d87b0540edc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>