Rename .js.es6 to .js in the admin application

app/assets/javascripts/admin/models/email-template.js

@@ -0,0 +1,13 @@
+import { ajax } from "discourse/lib/ajax";
+import RestModel from "discourse/models/rest";
+const { getProperties } = Ember;
+
+export default RestModel.extend({
+  revert() {
+    return ajax(`/admin/customize/email_templates/${this.id}`, {
+      method: "DELETE"
+    }).then(result =>
+      getProperties(result.email_template, "subject", "body", "can_revert")
+    );
+  }
+});