Add state_class to OHM sensors (home-assistant#125567)

* Minimum change required to get OHW into statistics

Not sure if there is any reason not to have this, my only idea would be that there would be that there are A LOT of values, but as far as I can see there are already long term data being stored about them anyway

* Update sensor.py

Guess that was an old way of doing it -_-

* Update sensor.py

remove spaces the break ruff -_-

* Update sensor.py

ruff is rough

homeassistant/components/openhardwaremonitor/sensor.py

@@ -11,6 +11,7 @@
 from homeassistant.components.sensor import (
     PLATFORM_SCHEMA as SENSOR_PLATFORM_SCHEMA,
     SensorEntity,
+    SensorStateClass,
 )
 from homeassistant.const import CONF_HOST, CONF_PORT
 from homeassistant.core import HomeAssistant
@@ -60,6 +61,8 @@ def setup_platform(
 class OpenHardwareMonitorDevice(SensorEntity):
     """Device used to display information from OpenHardwareMonitor."""
 
+    _attr_state_class = SensorStateClass.MEASUREMENT
+
     def __init__(self, data, name, path, unit_of_measurement):
         """Initialize an OpenHardwareMonitor sensor."""
         self._name = name