Merge "Adding a debug feature flag for taskbar pinning." into tm-qpr-dev am: b207102b

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/20956813



Change-Id: Id079dd46f57a13e7645bbf0d3240874c6cddbd26
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>