Steps to reproduce the issue

1. Install a component that has an administrator submenu link that uses an array url parameter. e.g.

<submenu>
    <menu link="option=com_plugins&amp;filter[folder]=system">System Plugins</menu>
</submenu>

2. Create a custom administrator menu
3. Click to add a new menu item on it

Expected result

No errors.
Ability to create a menu item using the submenu described above.

Actual result

The following error is seen:
Warning: strlen() expects parameter 1 to be string, array given in /home/181198.cloudwaysapps.com/njjxbtxwqr/public_html/administrator/components/com_menus/src/Model/MenutypesModel.php on line 458

Although a menu item can be created using the above mentioned submenu, the array url variable is removed and the link used is incorrect

System information (as much as possible)

Joomla v4.1.0
php v7.4.27
User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36

Additional comments