Allow custom middlewares into EnsureFrontendRequestsAreStateful

[coppolafab]

This PR enables the use of customized middlewares with EnsureFrontendRequestsAreStateful.

In a Laravel project where Illuminate\Session\Middleware\StartSession is replaced with a custom middleware, EnsureFrontendRequestsAreStateful was still using the default middleware.

This change will benefit developers who want to replace the default middlewares with their custom implementations.

Problem Description
In a Laravel + Sanctum project configured as follows:

<?php
return Application::configure(basePath: dirname(__DIR__))
    ->withMiddleware(static function (Middleware $middleware): void {
        $middleware->web(
            replace: [
                StartSession::class => CustomStartSession::class,
            ],
        );

        $middleware->statefulApi();
        // ...
});

The routes under api group does not use the custom StartSession, and EnsureFrontendRequestsAreStateful uses the default hardcoded middleware. This forces developers to copy and paste the frontendMiddleware method, risking it becoming out of sync with future updates to Sanctum.

Additionally, all other middleware used by EnsureFrontendRequestsAreStateful are already configurable.

[taylorotwell]

I am closing this pull request because it lacks sufficient explanation, tests, or both. It is difficult for us to merge pull requests without these things because the change may introduce breaking changes to the framework.

Feel free to re-submit your change with a thorough explanation of the feature and tests - integration tests are preferred over unit tests. Please include it's benefit to end users; the reasons it does not break any existing features; how it makes building web applications easier, etc.

Thanks!