Do not format menu differently for small screens

This looks really weird, especially when Spark window is resized with the menu opened and it suddenly jumps to a different layout, which in addtion is currently broken. We're also not testing this in any way, even manually. If we need this in future, we'll revisit.
Merge pull request #796 from ussuri/dont-reformat-menu-for-mobile

Do not format menu differently for small screens