docs(app): update angular to standalone (#3912)

Author: brandyscarney

static/usage/v8/app/set-focus/angular/example_component_ts.md

@@ -1,10 +1,12 @@
 ```ts
 import { Component } from '@angular/core';
+import { IonButton, IonRadio, IonRadioGroup } from '@ionic/angular/standalone';
 
 @Component({
   selector: 'app-example',
   templateUrl: 'example.component.html',
   styleUrls: ['example.component.css'],
+  imports: [IonButton, IonRadio, IonRadioGroup],
 })
 export class ExampleComponent {
   focusElement(id: string) {