Delete route always requires a resource request class when it should be optional

[lindyhopchris]

At the moment the delete route always expects there to be a resource request class, e.g. PostRequest. This is so that it can validate the delete request. However, implementing delete validation logic is entirely optional. Therefore, the delete route should work even when there isn't a resource request. It should just assume the deletion is allowed as the route has been registered and authorized by the time the deletion validation is attempted.