Fix for Road Congestion bug in long scenario

RBM Studio's Waterloo · published · build 18360914

This patch fixes an issue wherein a player could leave reinforcements off the board and use their last remaining road congestion moves to move on-board units. With this fix, if the number of road congestion moves remaining is <= the number of reinforcements, a reinforcement must be brought onto the map. Also fixes an issue wherein the AI would sometimes sneak in an extra illegal reinforcement placement after their road congestion moves were exhausted.