Fixes dashboard link not getting highlighted in the menu for small screens.  Note that it still doesn't work for Concept Coach, because that requires some js fixes.
Fixes dashboard link not getting highlighted in the menu for small screens.  Note that it still doesn't work for Concept Coach, because that requires some js fixes.

openstax/tutor-js,openstax/tutor-js,openstax/tutor-js,openstax/tutor-js,openstax/tutor-js