Take colour debt into account for direct challenges

[johndoknjas]

E.g., I just played as White against someone, and then submitted a random challenge to them (had missed their rematch). However, after they accepted I had White again. We also had only played on the day of, so no colour debt for me getting multiple Whites.

[hb20007]

It's the definition of "random"... Sometimes you will flip a coin and get 5 heads in a row.