fix extra keys not allowed

custom_components/tuya_local/devices/essentials_smart_electric_heater.yaml

@@ -59,8 +59,9 @@ entities:
         range:
           min: -5
           max: 5
-        scale: 0
-        step: 1
+        mapping:
+          - scale: 0
+            step: 1
   - entity: lock
     translation_key: child_lock
     category: config