Fix fan_modes in tuya climate

[springstan]

Description:

• TuyaClimate does not have a method called fan_modes() instead it is named fan_list()
• fixes the following error:

2020-01-02 11:05:21 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 286, in async_update_ha_state
    self._async_write_ha_state()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 327, in _async_write_ha_state
    attr.update(self.state_attributes or {})
  File "/usr/src/homeassistant/homeassistant/components/climate/__init__.py", line 229, in state_attributes
    data[ATTR_FAN_MODES] = self.fan_modes
  File "/usr/src/homeassistant/homeassistant/components/tuya/climate.py", line 123, in fan_modes
    return self.tuya.fan_modes()
AttributeError: 'TuyaClimate' object has no attribute 'fan_modes'

Related issue (if applicable): fixes #30382

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

[MartinHjelmare]

Thanks!