[automerger skipped] Add placeholder divider view when starting split tasks am: 32700f81ec -s ours

am skip reason: Merged-In I32e394a0bc361489473ee657161c8f3bcbf1e422 with SHA-1 cdaabc6199 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/26928404

Change-Id: I16e9fe62fadd42c9ab926cc1e2b3e828b6bb4f91
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>