adds file copyright header (#23103)

Author: rishabh-gupta-hashicorp

ui/packages/consul-ui/app/controllers/dc/services/show/instance.js

@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: BUSL-1.1
+ */
+
 import Controller from '@ember/controller';
 import { tracked } from '@glimmer/tracking';
 import { action } from '@ember/object';