Add missing translation string in dnsip (#127833)

homeassistant/components/dnsip/strings.json

@@ -11,6 +11,9 @@
         }
       }
     },
+    "abort": {
+      "already_configured": "[%key:common::config_flow::abort::already_configured_service%]"
+    },
     "error": {
       "invalid_hostname": "Invalid hostname"
     }