mychevy: Fix wrong attribute on battery level selector (home-assistan…

…t#20016)

The battery level sensor is broken because the logic for determining
if the battery is charged accessed the wrong variable. This one
character fix makes it work again.

homeassistant/components/sensor/mychevy.py

@@ -141,7 +141,7 @@ def _car(self):
     def icon(self):
         """Return the icon."""
         if self._attr == BATTERY_SENSOR:
-            charging = self.state_attributes.get("charging", False)
+            charging = self._state_attributes.get("charging", False)
             return icon_for_battery_level(self.state, charging)
         return self._icon