Merge "Use new onStartSplitLegacy when starting split from overview" into tm-dev am: 8aead5503f am: e17589f4b8

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/17779173

Change-Id: Ib73e94fdb7f113ba0838b857817648520d91bb02
Ignore-AOSP-First: this is an automerge
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>