Issue Boards: Flip caret on collapsed Closed list so it points to the right
Description
The carets on the Backlog and Closed lists in issue boards point in opposite directions.
The Closed list was originally supposed to open to the left, so the design used a caret that pointed that way. In the final implementation they actually both open to the right, so the two icons should face the same way
Proposal
Use a right-pointing caret for the Closed list