Duux Blizzard tests: clean up unused imports

tests/devices/test_duux_blizzard.py

@@ -1,8 +1,6 @@
-from homeassistant.components.climate.const import ClimateEntityFeature, HVACMode
-from homeassistant.const import UnitOfTemperature
+from homeassistant.components.climate.const import HVACMode
 
 from ..const import DUUX_BLIZZARD_PAYLOAD
-from ..helpers import assert_device_properties_set
 from ..mixins.climate import TargetTemperatureTests
 from .base_device_tests import TuyaDeviceTestCase