Hamburger menu should behave like a toggle instead of showing on hover

[jhung]

Describe the bug

The hamburger menu on mobile shows and hides in an unexpected manner. Hovering the icon reveals the menu, and selecting the hamburger menu while the menu is showing does not hide the menu.

Originally filed as FLOE-477

To reproduce

Steps to reproduce the behavior:

1. Go to https://guide.inclusivedesign.ca/
2. Resize the client so the hamburger menu appears
3. Hover over the hamburger icon
4. notice the menu appears without any user action and the menu does not hide if selecting the hamburger menu icon.

Expected behavior

The hamburger menu icon should behave like a toggle to show and hide the menu.