ui-v2 aside fix gap caused by overflow-y: auto
ui-v2 aside fix gap caused by overflow-y: auto

overflow-y: auto rule on aside/nav caused a gap to appear between the
side nav bar and top-nav entity selection bar.

This rule also caused aside menu icons to have more space on the left
than on the right.

Changing the overflow value to visible fixes both of these problems.

circleci/frontend,circleci/frontend,circleci/frontend