Rectec RT700 Grill: restore hvac_mode

In absense of an explanation, revert the removal of name to make the config valid again.

PR #2741

custom_components/tuya_local/devices/rectec_rt700_grill.yaml

@@ -9,6 +9,7 @@ entities:
     dps:
       - id: 1
         type: boolean
+        name: hvac_mode
         mapping:
           - dps_val: false
             value: "off"