Left navigation has horizontal scroll when `Show scroll bars` is set to `Always` in MacOS settings

Summary

If there is a vertical scroll bar in the left navigation there is also a horizontal scroll.

This happens in Chrome, Safari, and Firefox on MacOS only when you have Show scroll bars set to Always in the settings.

Steps to reproduce

1. Login as an Admin
2. Click "Menu" in the top nav
3. Click "Admin"
4. Resize the browser window so a vertical scroll bar appears in the left navigation
5. Scroll horizontally in left navigation

What is the current bug behavior?

Left navigation can be horizontally scrolled

What is the expected correct behavior?

No horizontal scroll on the left navigation

Relevant logs and/or screenshots

Screen_Recording_2021-06-14_at_8.36.56_AM

Possible fixes