I'm not sure I like this now that I've build it into Turbo Admin. Will have to see. (There's some niggles to fix first too)
It may be that it's better for where you have plugins that insist on having their own top-level menu item.
Reminder: The hidden items AND the open/closed state is saved not just within one site, but across all sites (if you use the browser extension).
So you can, for example, hide Yoast SEO *everywhere*!