Overkill: set sv_defaultplayermodel_* for pink and yellow teams

Looks like originally nobody considered overkill would be played with more than 2 teams so they didn't assign default models for pink and yellow. This caused the other 2 teams to get a mix of humans and robots. This MR gives yellow robots and pink humans. The order of teams seems to be red, blue, yellow, pink so now it alternates between robots and humans.