tests (goldair_gpph_heater): remove now unused SensorDeviceClass

tests/devices/test_goldair_gpph_heater.py

@@ -1,6 +1,5 @@
 from homeassistant.components.binary_sensor import BinarySensorDeviceClass
 from homeassistant.components.climate.const import ClimateEntityFeature, HVACMode
-from homeassistant.components.sensor import SensorDeviceClass
 from homeassistant.const import (
     PERCENTAGE,
     PRECISION_WHOLE,