Given an instance of an actor, find the wrapped asset object which can be used to create a validFAssetData. Returns nullptr if the given ActorInstance is not valid for this factory. Override this function if the factory actor is a different class than the asset data's class which this factory operates on. For example, if this is the static mesh actor factory, the class of the asset data isUStaticMesh, but the actor factory's class isAStaticMeshActor