minor #1254 [Site] Use AssetMapper for 6.4 for install (weaverryan)

This PR was squashed before being merged into the 2.x branch.

Discussion
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[Site] Use AssetMapper for 6.4 for install

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Issues        | None
| License       | MIT

Waiting for AssetMapper 6.4 release.

The only problem now is... the install instructions are so short, the terminal block seems unnecessarily huge...

<img width="1212" alt="Screenshot 2023-11-06 at 4 18 47 PM" src="https://github.com/symfony/ux/assets/121003/e29e44d9-caaa-4038-85b2-1120ae593d81">

Commits
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7b13c15 [Site] Use AssetMapper for 6.4 for install

ux.symfony.com/templates/main/homepage.html.twig

@@ -31,10 +31,8 @@
 
     <div class="row">
         <div class="col-12 col-md-6">
-            <twig:Terminal>
-                composer require symfony/webpack-encore-bundle symfony/stimulus-bundle
-                npm install
-                npm run watch
+            <twig:Terminal bottomPadding="145">
+                composer require symfony/asset-mapper symfony/stimulus-bundle
             </twig:Terminal>
         </div>