Adjust lutron_caseta type hints (#73840)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

homeassistant/components/lutron_caseta/fan.py

@@ -86,6 +86,6 @@ class LutronCasetaFan(LutronCasetaDeviceUpdatableEntity, FanEntity):
         await self._smartbridge.set_fan(self.device_id, named_speed)
 
     @property
-    def is_on(self):
+    def is_on(self) -> bool:
         """Return true if device is on."""
-        return self.percentage and self.percentage > 0
+        return bool(self.percentage)