[9.x] Add support for passing array as the second parameter for the group method.

[hossein-zare]

Hi.

What's this PR for? (example):
in the RouteServiceProvider file:

Route::middleware('web')
   ->namespace($this->namespace)
      ->group(base_path('routes/account/web.php'));

Route::middleware('web')
   ->namespace($this->namespace)
      ->group(base_path('routes/account/staff.php'));

can be written as follows

Route::middleware('web')
   ->namespace($this->namespace)
      ->group([
         base_path('routes/account/web.php'),
         base_path('routes/account/staff.php')
       ]);

Both of them with the same middleware and namespace in just an array.

Reasons why this PR won't break other features:

1. The original group method only accepts \Closure|string as the second parameter which is $routes, so passing an array won't mess around.

   The original group:

   /**
     * Create a route group with shared attributes.
    *
    * @param  array  $attributes
    * @param  \Closure|string  $routes
    * @return void
    */
   public function group(array $attributes, $routes)

2. It's only one simple commit, I also tested it on a real/ready project.

I ❤ Laravel

[aronpc]

#28418