[Refresh] Navigation does not work without JavaScript enabled

[alexgibson]

Description

The new navigation is reliant on JavaScript to function. The hover menus should at least be able to function using just CSS, and then be progressively enhanced when JS executes. Not a lot of people disable JavaScript, but a navigation that works via progressive enhancement is more reliable and robust if a JS error should occur.

Steps to reproduce

1. Set M24_WEBSITE_REFRESH to active in the DB.
2. Run npm start
3. Open http://localhost:8000/en-US/
4. Open dev tools and disable JavaScript in the settings menu.
5. Refresh the page.
6. Hover over a menu item with the mouse.

Expected result

The navigation menu should open.

Actual result

The navigation menu is inaccessible.

Environment

macOS
Firefox Nightly