In customizer, top-level dropdown links are active -- please disable

Description

When you're editing a menu in the customizer, top-level dropdown toggles are not working properly. Rather than toggling the dropdown, they are linking to the page. This may cause content editors to construct their menus differently from how they'll perform on the site. Please make the customizer functionally consistent with the standard dropdown toggle functionality.

Examples

Customer/Requester Info

Name: Jonathan Dedering

Email: jonathan.dedering@wisc.edu

Website: psl.wiscweb.wisc.edu