Address late review in Overkiz (add duration device class) (#77778)

Address follow-up review in Overkiz (duration device class)

homeassistant/components/overkiz/sensor.py

@@ -354,14 +354,14 @@ SENSOR_DESCRIPTIONS: list[OverkizSensorDescription] = [
     OverkizSensorDescription(
         key=OverkizState.IO_HEAT_PUMP_OPERATING_TIME,
         name="Heat Pump Operating Time",
-        icon="mdi:home-clock",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         native_unit_of_measurement=TIME_SECONDS,
     ),
     OverkizSensorDescription(
         key=OverkizState.IO_ELECTRIC_BOOSTER_OPERATING_TIME,
         name="Electric Booster Operating Time",
-        icon="mdi:home-clock",
+        device_class=SensorDeviceClass.DURATION,
         native_unit_of_measurement=TIME_SECONDS,
         entity_category=EntityCategory.DIAGNOSTIC,
     ),