fix: MTTB-1273 Inconsistent SceneName in SceneEvent (#3458)

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[MTTB-1278](https://jira.unity3d.com/browse/MTTB-1273)
fixes: #3418 

## Changelog

- Added: A `ScenePath` field on the `SceneEvent` returned by the
`OnSceneEvent` callback.
- Fixed: Various bugs around the `OnSceneEvent` callback.

## Testing and Documentation

- Includes unit tests.

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## Backport

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Backport not yet created.

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Co-authored-by: Noel Stephens <[email protected]>

Author: EmandM

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -15,6 +15,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ### Fixed
 
 - Fixed issue where `NetworkVariable`s on a `NetworkBehaviour` could fail to synchronize changes if one has `NetworkVariableUpdateTraits` set and is dirty but is not ready to send. (#3466)
+- Fixed inconsistencies in the `OnSceneEvent` callback. (#3458)
 - Fixed issues with the `NetworkBehaviour` and `NetworkVariable` length safety checks. (#3405)
 - Fixed memory leaks when domain reload is disabled. (#3427)
 - Fixed an exception being thrown when unregistering a custom message handler from within the registered callback. (#3417)