docs(back-button): update angular to standalone

Author: brandyscarney

static/usage/v7/back-button/basic/angular/example_component_ts.md

@@ -1,11 +1,13 @@
 ```ts
 import { Component } from '@angular/core';
+import { IonNav } from '@ionic/angular/standalone';
 
 import { PageOneComponent } from './page-one.component';
 
 @Component({
   selector: 'app-example',
   templateUrl: 'example.component.html',
+  imports: [IonNav],
 })
 export class ExampleComponent {
   component = PageOneComponent;

static/usage/v7/back-button/custom/angular/example_component_ts.md

@@ -1,11 +1,13 @@
 ```ts
 import { Component } from '@angular/core';
+import { IonNav } from '@ionic/angular/standalone';
 
 import { PageOneComponent } from './page-one.component';
 
 @Component({
   selector: 'app-example',
   templateUrl: 'example.component.html',
+  imports: [IonNav],
 })
 export class ExampleComponent {
   component = PageOneComponent;

static/usage/v8/back-button/basic/angular/example_component_ts.md

@@ -1,11 +1,13 @@
 ```ts
 import { Component } from '@angular/core';
+import { IonNav } from '@ionic/angular/standalone';
 
 import { PageOneComponent } from './page-one.component';
 
 @Component({
   selector: 'app-example',
   templateUrl: 'example.component.html',
+  imports: [IonNav],
 })
 export class ExampleComponent {
   component = PageOneComponent;

static/usage/v8/back-button/custom/angular/example_component_ts.md

@@ -1,11 +1,13 @@
 ```ts
 import { Component } from '@angular/core';
+import { IonNav } from '@ionic/angular/standalone';
 
 import { PageOneComponent } from './page-one.component';
 
 @Component({
   selector: 'app-example',
   templateUrl: 'example.component.html',
+  imports: [IonNav],
 })
 export class ExampleComponent {
   component = PageOneComponent;