fix(modena_es15sky_waterheater): hide non-working energy sensor

Hide this entity by default to reduce confusion.

Discussion #3557

custom_components/tuya_local/devices/modena_es15sky_waterheater.yaml

@@ -57,6 +57,7 @@ entities:
   - entity: sensor
     name: Energy
     category: diagnostic
+    hidden: true
     dps:
       - id: 10
         type: integer