Fix splitscreen Title Card act name regression
This merge request fixes a regression caused by commit 5568e445 ("Colored title cards").
That commit set
&players[consoleplayer] at the start of
ST_drawTitleCard() in order to get the local player's colour... but
stplyr is checked later in the same function, both for the sake of checking whether player 1 or player 2's title card is being drawn, and for offsetting the act name downwards with
V_PERPLAYER so that the act name is shown on both players' views. Neither of those things happen in v2.2.3, due to
stplyr being set to player 1 first.
This merge request fixes that, by not setting
stplyr to anything, and instead checking
colormap currently doesn't apply to anything drawn for player 2, so it's okay that
colormap only matches player 1.)