fix: In-Scene Placed Object Parenting and Serialization Order (back port)

[NoelStephensUnity]

This is the back port of #3387 that resolves some issues with in-scene placed NetworkObjects in parent-child hierarchy and the synchronization of late joining clients when the hierarchy has changed from that of its default hierarchy defined within the scene.

MTT-11883

Changelog

• Fixed: Issue where in-scene placed NetworkObjects could fail to synchronize its transform properly (especially without a NetworkTransform) if their parenting changes from the default when the scene is loaded and if the same scene remains loaded between network sessions while the parenting is completely different from the original hierarchy.
• Changed: The scene loading event serialization order for in-scene placed NetworkObjects to be based on their parent-child hierarchy.

Testing and Documentation

• Includes no additional tests (requires manual testing due to scene loading constraints).
• No documentation changes or additions were necessary.