[BUG] Extensions in overflow menu don't have full width

[AdamXweb]

Describe the bug
Any extensions in the overflow menu don't respect the full width of the extension.
Can read more about the issue here:
https://www.reddit.com/r/FirefoxCSS/comments/n9asta/addons_width_changes_to_a_fixed_value_when_placed/
@aminomancer has a fix using a script to scroll through extensions:
https://github.com/aminomancer/uc.css.js/blob/master/JS/navbarToolbarButtonSlider.uc.js

Other option is to define each extension's width individually.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
How it should be (how it is in toolbar)

How it looks in overflow menu

Desktop (please complete the following information):

• OS: MacOS 11
• Firefox version 92
• WhiteSur theme: latest commit

Hope this helps someone else in the future