Network prefabs are not registered for objects spawned within injected tiles

[Zaggy1024]

Prefabs that are supposed to be network-spawned from SpawnSyncedObject instances are not found when they are contained by a tile that is injected through DungeonFlow.TileInjectionRules, due to the fact that DungeonFlow.GetTiles() doesn't check for the tiles contained by those injection rules.

A custom apparatus spawned in the Tomb interior is not registered as network prefab and fails to spawn for other clients.

[Zaggy1024]

It should be possible to work around this by adding any custom items spawned within injected tiles as registered ExtendedItems.