fix(rheem_ehg_waterheater): use correct dp naming

custom_components/tuya_local/devices/rheem_ehg_waterheater.yaml

@@ -8,7 +8,7 @@ entities:
     dps:
       - id: 1
         type: boolean
-        name: operating_mode
+        name: operation_mode
         mapping:
           - dps_val: false
             value: "off"