Gosund WP9RTL: fix translation placeholder, rename USB switch

- fix for last change (placeholders are not a list)
- rename USB switch to USB, as switch is implied by the entity type

custom_components/tuya_local/devices/gosund_wp9rtl_3_outlet_usb_child_lock_and_state.yaml

@@ -59,7 +59,7 @@ entities:
         name: inching
         type: string
   - entity: switch
-    name: USB switch
+    name: USB
     class: switch
     dps:
       - id: 7
@@ -130,7 +130,7 @@ entities:
     class: duration
     translation_key: timer_x
     translation_placeholders:
-      - x: USB
+      x: USB
     dps:
       - id: 15
         name: value