Add and use percentage constant (#32094)

* Add and use percentage constant

* Fix pylint error and broken test

homeassistant/components/bloomsky/sensor.py

@@ -4,7 +4,12 @@ import logging
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import CONF_MONITORED_CONDITIONS, TEMP_CELSIUS, TEMP_FAHRENHEIT
+from homeassistant.const import (
+    CONF_MONITORED_CONDITIONS,
+    TEMP_CELSIUS,
+    TEMP_FAHRENHEIT,
+    UNIT_PERCENTAGE,
+)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
 
@@ -25,7 +30,7 @@ SENSOR_TYPES = [
 # Sensor units - these do not currently align with the API documentation
 SENSOR_UNITS_IMPERIAL = {
     "Temperature": TEMP_FAHRENHEIT,
-    "Humidity": "%",
+    "Humidity": UNIT_PERCENTAGE,
     "Pressure": "inHg",
     "Luminance": "cd/m²",
     "Voltage": "mV",
@@ -34,7 +39,7 @@ SENSOR_UNITS_IMPERIAL = {
 # Metric units
 SENSOR_UNITS_METRIC = {
     "Temperature": TEMP_CELSIUS,
-    "Humidity": "%",
+    "Humidity": UNIT_PERCENTAGE,
     "Pressure": "mbar",
     "Luminance": "cd/m²",
     "Voltage": "mV",