Allow `PhaserScene` to accept either a scene instance or a scene constructor. This enables more flexible scene registration within the `PhaserBridge`. Also updates `sceneKey` to be optional, defaulting to the scene's internal key.
Allow `PhaserScene` to accept either a scene instance or a scene constructor. This enables more flexible scene registration within the `PhaserBridge`. Also updates `sceneKey` to be optional, defaulting to the scene's internal key.