Remove the MP tooltip row from campaign missions.

This is something that has always bugged me about the "recent" (2012 and later) singleplayer missions.  The player name and flag are not necessary in the sp missions (where each faction has a distinct color), and feel out of place.  Removing this row from the tooltip adds a bit of minor polish.
It may be gross, but it's the most (the only, even) reliable way we have to determine whether a map is a scripted mission or not.