Fixed: the next level and countdown time didn't update on the scoreboard when the server used the "changemap" CCMD in the middle of an intermission.

While on the intermission screen in online games, if cl_intermissiontimer is enabled, then a message like this will appear on the scoreboard's main header: Entering MAP01: Entryway in 20 second(s).

If the server host decides to change the level to-be-entered in the middle of the intermission via changemap, then the level and countdown time (which resets on the server's end) won't update correctly on the scoreboard. This MR fixes that discrepancy.