Update solax state class for sensors with no units (#92914)

Update sensor.py

Units.NONE is used for text entities which are not measurements.
Marking them so breaks their history.

homeassistant/components/solax/sensor.py

@@ -87,7 +87,6 @@ SENSOR_DESCRIPTIONS: dict[tuple[Units, bool], SensorEntityDescription] = {
     ),
     (Units.NONE, False): SensorEntityDescription(
         key=f"{Units.NONE}_{False}",
-        state_class=SensorStateClass.MEASUREMENT,
     ),
 }