Fix battery unavailable

Author: andrew-codechimp

custom_components/battery_notes/binary_sensor.py

@@ -238,7 +238,7 @@ async def async_state_changed_listener(
 
         if (
             wrapped_battery_state := self.hass.states.get(self._battery_entity_id)
-        ) is None or wrapped_battery_state.state == STATE_UNAVAILABLE:
+        ) is None or wrapped_battery_state.state in [STATE_UNAVAILABLE, STATE_UNKNOWN]:
             self._attr_is_on = False
             self._attr_available = True
             return