The unified banner's mode selector wasn't working on mobile, the menu

wouldn't open on touch. This is because the mode menu didn't specifically

handle touch events. We now handle touch events and make sure the menu

works as normal on mobile.

Opened and closed the menu on mobile, tapping on different parts of it

  (the label, icon, empty space).
Switched between menu modes by clicking on the menu items.
Made sure the menu still worked on desktop.