Allow OpenUV entities to be unavailable (#31018)

* Allow OpenUV entities to be unavailable

* Empty commit to re-trigger build

homeassistant/components/openuv/binary_sensor.py

@@ -100,8 +100,11 @@ class OpenUvBinarySensor(OpenUvEntity, BinarySensorDevice):
         data = self.openuv.data[DATA_PROTECTION_WINDOW]
 
         if not data:
+            self._available = False
             return
 
+        self._available = True
+
         for key in ("from_time", "to_time", "from_uv", "to_uv"):
             if not data.get(key):
                 _LOGGER.info("Skipping update due to missing data: %s", key)