add router service to controllers to avoid deprecation

assets/javascripts/discourse/controllers/admin-wizards-api-show.js.es6

@@ -7,8 +7,11 @@ import { selectKitContent } from "../lib/wizard";
 import { underscore } from "@ember/string";
 import Controller from "@ember/controller";
 import I18n from "I18n";
+import { inject as service } from '@ember/service';
 
 export default Controller.extend({
+  router: service(),
+
   queryParams: ["refresh_list"],
   loadingSubscriptions: false,
   notAuthorized: not("api.authorized"),
@@ -248,7 +251,7 @@ export default Controller.extend({
         .catch(popupAjaxError)
         .then((result) => {
           if (result.success) {
-            this.transitionToRoute("adminWizardsApis").then(() => {
+            this.router.transitionToRoute("adminWizardsApis").then(() => {
               this.send("refreshModel");
             });
           }

assets/javascripts/discourse/controllers/custom-wizard-step.js.es6

@@ -1,7 +1,9 @@
 import Controller from "@ember/controller";
 import getUrl from "discourse-common/lib/get-url";
+import { inject as service } from '@ember/service';
 
 export default Controller.extend({
+  router: service(),
   wizard: null,
   step: null,
 
@@ -15,12 +17,12 @@ export default Controller.extend({
         const wizardId = this.get("wizard.id");
         window.location.href = getUrl(`/w/${wizardId}/steps/${nextStepId}`);
       } else {
-        this.transitionToRoute("customWizardStep", nextStepId);
+        this.router.transitionToRoute("customWizardStep", nextStepId);
       }
     },
 
     goBack() {
-      this.transitionToRoute("customWizardStep", this.get("step.previous"));
+      this.router.transitionToRoute("customWizardStep", this.get("step.previous"));
     },
 
     showMessage(message) {