[9.x] Fix registering event listeners with array callback

[Digity101]

• Laravel Version: 9.26
• PHP Version: 8.1.1

Description:

In Laravel 9.x according to the docs, you could register listeners with in EventServiceProvider with the array syntax. I.E

class EventServiceProvider extends ServiceProvider { 
  /**
   * The event listener mappings for the application.
   *
   * @var array
   */
  protected $listen = [
      OrderShipped::class => [
          [SendShipmentNotification::class, 'handle'],
      ],
  ];
}

However, if you register multiple listeners with the array syntax, then you get an array to string conversion error

Steps To Reproduce:

class EventServiceProvider extends ServiceProvider { 
 /**
  * The event listener mappings for the application.
  *
  * @var array
  */
 protected $listen = [
     OrderShipped::class => [
         [SendShipmentNotification::class, 'handle'],
         [SendShipmentNotification::class, 'handle2'],
     ],
 ];
}

Fix:

The EventServiceProvider uses array_unique to get unique listeners, however the default behavior is to compare items as strings. Giving the flag SORT_REGULAR fixes the issue.