fix (mire_qtower_humidifier): device uses "middle" not "medium"

Issue #4107

custom_components/tuya_local/devices/miro_qtower_humidifier.yaml

@@ -122,7 +122,7 @@ entities:
             value: "off"
           - dps_val: low
             value: low
-          - dps_val: medium
+          - dps_val: middle
             value: high
   - entity: switch
     name: Mute