#169365 introduces the LaunchEngine for backwards compatibility after the UISceneDelegate. #169399 introduces an alternative.

There is a draft migration guide: https://docs.google.com/document/d/16WsqYbANmhupw-gxGPQPZ9B3yz1YBIviS-N1UyIQNSE/edit?tab=t.0#heading=h.txry2otwqko3

Once the migration guide is published we should add a runtime check that points to it if the LaunchEngine is used.