By Luc Cohen NEW YORK (Reuters) – A lawyer for three Black coaches accusing the National Football League of racist hiring on Monday told a federal judge their case should not be sent to arbitration because the designated mediator, league commissioner Roger Goodell, was biased. Former Miami Dolphins head coach Brian Flores and two other coaches are suing the league and its 32 teams for alleged discrimination when filling coaching and senior management jobs. The NFL last month said the claims lacked merit, and asked U.S. District Judge Valerie Caproni in Manhattan to either dismiss the case or s…