Improve upon keyboard accessibility of menu in website header

[jasonnrosa]

Severity: Low

Description: Currently keyboard navigation works within the menu of the website header module but if you tab all the way out of a menu the menu you were just in doesn't collapse. This is technically how it works via our reference here (https://www.w3.org/WAI/tutorials/menus/flyout) however the solution they use doesn't scale to multiple levels of child items. We'll need to figure out our own solution to support this. I don't think this is a big issue at the moment but certainly something we would like to improve upon.

Remediation: When you tab all the way through a drop down menu and land on the next parent menu item that last drop down menu should collapse (currently you can do this manually by re-clicking the toggles).