docs(docs-infra): fix first-app intro example (#61042)

fixes #60844

PR Close #61042

adev/src/content/tutorials/first-app/intro/app.component.ts

@@ -0,0 +1,9 @@
+import {Component} from '@angular/core';
+
+@Component({
+  selector: 'app-root',
+  template: `
+    Welcome to Angular!
+  `,
+})
+export class AppComponent {}

adev/src/content/tutorials/first-app/intro/config.json

@@ -1,7 +1,6 @@
 {
   "title": "Your first Angular app",
   "type": "editor",
-  "src": "../steps/14-http/src",
-  "nextTutorial": "learn-angular",
-  "openFiles": ["src/app/app.component.ts"]
+  "nextTutorial": "first-app",
+  "openFiles": ["app.component.ts"]
 }