Adjust error handling for Gigya JSONDecodeError

[epenet]

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/config_entries.py", line 382, in async_setup
    result = await component.async_setup_entry(hass, self)
  File "/usr/src/homeassistant/homeassistant/components/renault/__init__.py", line 28, in async_setup_entry
    await renault_hub.async_initialise(config_entry)
  File "/usr/src/homeassistant/homeassistant/components/renault/renault_hub.py", line 59, in async_initialise
    vehicles = await self._account.get_vehicles()
  File "/usr/local/lib/python3.10/site-packages/renault_api/renault_account.py", line 62, in get_vehicles
    return await self.session.get_account_vehicles(
  File "/usr/local/lib/python3.10/site-packages/renault_api/renault_session.py", line 192, in get_account_vehicles
    gigya_jwt=await self._get_jwt(),
  File "/usr/local/lib/python3.10/site-packages/renault_api/renault_session.py", line 142, in _get_jwt
    response = await gigya.get_jwt(
  File "/usr/local/lib/python3.10/site-packages/renault_api/gigya/__init__.py", line 102, in get_jwt
    await request(
  File "/usr/local/lib/python3.10/site-packages/renault_api/gigya/__init__.py", line 38, in request
    gigya_response: models.GigyaResponse = schema.loads(response_text)
  File "/usr/local/lib/python3.10/site-packages/marshmallow/schema.py", line 755, in loads
    data = self.opts.render_module.loads(json_data, **kwargs)
  File "/usr/local/lib/python3.10/json/__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File "/usr/local/lib/python3.10/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/local/lib/python3.10/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)