feat(LaratrustMiddleware@unauthorized): Add JSON response handling for unauthorized access

[Nicodav28]

What’s New?

• Added JSON response handling to unauthorized() method in LaratrustMiddleware.
• If laratrust.middleware.handling is set to json, the middleware will return a structured JSON response instead of redirecting or aborting.

---

Why This Change?

• Improves API support by providing standardized JSON responses.
• Enhances maintainability and scalability by allowing response customization via config/laratrust.php.

---

Changes Made

• Updated unauthorized() to support JSON response.
• Introduced a new json handling option in config/laratrust.php, with:
  • Customizable HTTP status code (code).
  • Optional timestamp inclusion (include_timestamp).
  • Flexible response structure (structure).
• Maintained full compatibility with existing abort and redirect handlers.

---

How to Test?

1. Update config/laratrust.php:

    'middleware' => [
        /**
         * Define if the laratrust middleware are registered automatically in the service provider.
         */
        'register' => true,
   
        /**
         * Method to be called in the middleware return case.
         * Available: abort|redirect.
         */
        'handling' => 'json',
   
        /**
         * Handlers for the unauthorized method in the middlewares.
         * The name of the handler must be the same as the handling.
         */
        'handlers' => [
            /**
             * Aborts the execution with a 403 code and allows you to provide the response text.
             */
            'abort' => [
                'code' => 403,
                'message' => 'User does not have any of the necessary access rights.',
            ],
   
            /**
             * Redirects the user to the given url.
             * If you want to flash a key to the session,
             * you can do it by setting the key and the content of the message
             * If the message content is empty it won't be added to the redirection.
             */
            'redirect' => [
                'url' => '/home',
                'message' => [
                    'key' => 'error',
                    'content' => '',
                ],
            ],
   
   
            /**
             * Defines a custom JSON response format for unauthorized access.
             * This can be used when a JSON response is preferred over a redirect or abort.
             *
             * - 'code': The HTTP status code to return (default: 403).
             * - 'include_timestamp': Whether to include a timestamp in the response (true/false).
             * - 'structure': Defines the JSON response format.
             */
            'json'     => [
                'code'              => 403,
                'include_timestamp' => false,
                'structure'         => [
                    'status'  => 'error',
                    'message' => 'User does not have the necessary access rights to perform this action.',
                ],
            ],
        ],
    ],

2. Run php artisan config:clear to apply the changes.
3. Trigger an unauthorized request (e.g., accessing a protected route without permissions).
4. You should receive a JSON response like:

   {
       "status": "error",
       "message": "User does not have the necessary access rights to perform this action.",
       "timestamp": "2024-07-01T12:34:56.789Z"
   }

---

Let me know if you need any adjustments

[Nicodav28]

@santigarcor Would you like to give a brief review to this PR, I can make any adjustment you consider pertinent to approve this PR, please and thank you!

[santigarcor]

What if instead of returning a json the configuration allows for a custom response handler? Like an invokable class that returns a response? In that way you can do whatever you want.