fix: Submenus in small screens get cut off

[caseyfaber]

🐛 Bug Report

If menu has submenus, they aren't usable on small screen sizes as the submenu items get cut off.

💻 Repro or Code Sample

Sandbox: https://codesandbox.io/s/fast-submenu-issue-forked-tmommy?file=/index.html

1. Resize display area to 400px or less
2. Hover over Menu item 3

🤔 Expected Behavior

Perhaps the anchored region could position differently, like to the bottom or top, if there is no space to the right or left.

😯 Current Behavior

The submenu items are cut off.

🔦 Context

We have a context menu made with menu, with a submenu inside a menu item, and during accessibility testing a bug was filed where submenus are cut off when the window is 320px, which makes it not pass accessibility requirements.

🌍 Your Environment

• OS & Device: Windows
• Browser: Edge, Chrome, Firefox
• Version: fast-foundation 2.46.8

[Yashi1201]

GitHub Tags:#LinkedBug;#Linked:Bug39148928;

Primary Bug Link : https://microsoft.visualstudio.com/OSGS/_workitems/edit/39148928

[scomea]

Fix in progress. Should have something up in the next few days.

[chrisdholt]

I believe this has been closed both by the issues above and the migration to floating ui.