Fix 0°C when the temperature is unavailable in HKO API (#162052)

homeassistant/components/hko/coordinator.py

@@ -119,7 +119,7 @@ class HKOUpdateCoordinator(DataUpdateCoordinator[dict[str, Any]]):
                     for item in data[API_TEMPERATURE][API_DATA]
                     if item[API_PLACE] == self.location
                 ),
-                0,
+                None,
             ),
         }