remove "Customize Default Action" doc section

Author: kbond

src/LiveComponent/README.md

@@ -541,26 +541,6 @@ class RandomNumberComponent
 }
 ```
 
-### Customize Default Action
-
-The default component action is `__invoke()` by default. You
-can customize the method with the `AsLiveComponent` attribute:
-
-```php
-// src/Components/ProductSearchComponent.php
-namespace App\Components;
-
-use Symfony\UX\LiveComponent\Attribute\AsLiveComponent;
-
-#[AsLiveComponent('product_search', defaultAction: 'defaultAction()')]
-class ProductSearchComponent
-{
-    public function defaultAction(): void
-    {
-    }
-}
-```
-
 ### Actions and CSRF Protection
 
 When you trigger an action, a POST request is sent that contains