Korex kettle: fix incorrect change to mapping for unit

custom_components/tuya_local/devices/korex_axwf306n_smart_kettle.yaml

@@ -102,10 +102,10 @@ entities:
         type: string
         name: temperature_unit
         mapping:
-          - dps_val: C
-            value: true
-          - dps_val: F
-            value: false
+          - dps_val: c
+            value: C
+          - dps_val: f
+            value: F
   - entity: sensor
     translation_key: status
     class: enum