[BUG] Object of type Url is not JSON serializable

[jleclanche]

Describe the bug
django-ninja = "^1.3.0"

Using HttpUrl (or, I suspect, any *Url class) for a schema used in a response results in json serialization error. This is the same type of issue as #717.

Traceback (most recent call last):
  File "/home/adys/.cache/pypoetry/virtualenvs/fabrile-backend-fklT6p4J-py3.10/lib/python3.10/site-packages/ninja/operation.py", line 121, in run
    return self._result_to_response(request, result, temporal_response)
  File "/home/adys/.cache/pypoetry/virtualenvs/fabrile-backend-fklT6p4J-py3.10/lib/python3.10/site-packages/ninja/operation.py", line 278, in _result_to_response
    return self.api.create_response(
  File "/home/adys/.cache/pypoetry/virtualenvs/fabrile-backend-fklT6p4J-py3.10/lib/python3.10/site-packages/ninja/main.py", line 453, in create_response
    content = self.renderer.render(request, data, response_status=status)
  File "/home/adys/.cache/pypoetry/virtualenvs/fabrile-backend-fklT6p4J-py3.10/lib/python3.10/site-packages/ninja/renderers.py", line 25, in render
    return json.dumps(data, cls=self.encoder_class, **self.json_dumps_params)
  File "/usr/lib/python3.10/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.10/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.10/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/home/adys/.cache/pypoetry/virtualenvs/fabrile-backend-fklT6p4J-py3.10/lib/python3.10/site-packages/ninja/responses.py", line 28, in default
    return super().default(o)
  File "/home/adys/.cache/pypoetry/virtualenvs/fabrile-backend-fklT6p4J-py3.10/lib/python3.10/site-packages/django/core/serializers/json.py", line 106, in default
    return super().default(o)
  File "/usr/lib/python3.10/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type Url is not JSON serializable