Revert "Remove check for preventing re-parenting non-split apps"

Revert "Use new onStartSplitLegacy when starting split from overview"

Revert submission 17779173-startSplitLegacy

Reason for revert: Broken build: b/230129218
Reverted Changes:
I01590e53c:Remove check for preventing re-parenting non-split...
I696749f76:Use new onStartSplitLegacy when starting split fro...

Change-Id: I754bc308f37eea2fc50eda2b9df068adf711a268