Handle lutron_caseta fan speed being none (#47120)

homeassistant/components/lutron_caseta/fan.py

@@ -44,6 +44,8 @@ class LutronCasetaFan(LutronCasetaDevice, FanEntity):
     @property
     def percentage(self) -> str:
         """Return the current speed percentage."""
+        if self._device["fan_speed"] is None:
+            return None
         return ordered_list_item_to_percentage(
             ORDERED_NAMED_FAN_SPEEDS, self._device["fan_speed"]
         )