Bugfix: device class for wheel sensor cannot be 'none'

[stegm]

The 'device_class' attribute cannot contain the value 'none', but can omitted completely instead.

[mathieu-clement]

Any ETA on this?

Home Assistant is logging errors for this reason:

2022-10-21 12:24:43.943 ERROR (MainThread) [homeassistant.util.logging] Exception in async_discover when dispatching 'mqtt_discovery_new_sensor_mqtt': ({'name': 'myStrom Wifi Button wheel', 'state_topic': 'mystrom2mqtt/BCFF4D4A0243/wheel/state', 'device_class': None, 'unique_id': 'BCFF4D4A0243_wheel_mystrom2mqtt', 'device': {'identifiers': 'mystrom_BCFF4D4A0243', 'connections': [['mac', 'bc:ff:4d:4a:02:43']], 'model': 'myStrom Button', 'name': 'BCFF4D4A0243', 'manufacturer': 'myStrom AG', 'via_device': 'mystrom2mqtt'}, 'platform': 'mqtt'},)
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/mqtt/mixins.py", line 315, in async_discover
    config = discovery_schema(discovery_payload)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/validators.py", line 232, in __call__
    return self._exec((Schema(val) for val in self.validators), v)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/validators.py", line 355, in _exec
    raise e if self.msg is None else AllInvalid(self.msg, path=path)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/validators.py", line 351, in _exec
    v = func(v)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/schema_builder.py", line 272, in __call__
    return self._compiled([], data)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/schema_builder.py", line 818, in validate_callable
    return schema(data)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/schema_builder.py", line 272, in __call__
    return self._compiled([], data)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/schema_builder.py", line 595, in validate_dict
    return base_validate(path, iteritems(data), out)
  File "/usr/local/lib/python3.10/site-packages/voluptuous/schema_builder.py", line 433, in validate_mapping
    raise er.MultipleInvalid(errors)
voluptuous.error.MultipleInvalid: expected SensorDeviceClass or one of 'apparent_power', 'aqi', 'battery', 'carbon_monoxide', 'carbon_dioxide', 'current', 'date', 'distance', 'duration', 'energy', 'frequency', 'gas', 'humidity', 'illuminance', 'moisture', 'monetary', 'nitrogen_dioxide', 'nitrogen_monoxide', 'nitrous_oxide', 'ozone', 'pm1', 'pm10', 'pm25', 'power_factor', 'power', 'pressure', 'reactive_power', 'signal_strength', 'speed', 'sulphur_dioxide', 'temperature', 'timestamp', 'volatile_organic_compounds', 'voltage', 'volume', 'weight' for dictionary value @ data['device_class']