feat: add cookie assertions

[geisi]

Hi PestPHP team,

thank you for the awesome Pest v4 release and the new browser testing plugin.

This PR introduces functionalities to do assertions on cookies when visiting pages.

This is especially useful when you want to test applications that have some custom cookie logic. E.g. testing cookie security mechanisms, impersonation or login functionalities.

New Assertions added in this PR

$page = visit('https://laravel.com');

$page->assertHasCookie('laravel');
$page->assertCookieMissing('django');
$page->assertNoCookies();