Cleanup unused loggers (components N-Z + tests) (#41982)

homeassistant/util/unit_system.py

@@ -1,6 +1,4 @@
 """Unit system helper class and methods."""
-
-import logging
 from numbers import Number
 from typing import Optional
 
@@ -33,8 +31,6 @@ from homeassistant.util import (
     volume as volume_util,
 )
 
-_LOGGER = logging.getLogger(__name__)
-
 LENGTH_UNITS = distance_util.VALID_UNITS
 
 MASS_UNITS = [MASS_POUNDS, MASS_OUNCES, MASS_KILOGRAMS, MASS_GRAMS]