WASHINGTON — A federal judge on Monday dismissed antitrust lawsuits brought against Facebook by the Federal Trade Commission and a coalition of state attorneys general, dealing a significant blow to attempts by regulators to rein in tech giants.U.S. District Judge James Boasberg ruled Monday that the lawsuits were “legally insufficient” and didn’t provide enough evidence to prove that Facebook was a monopoly. The ruling dismisses the complaint but not the case, meaning the FTC could refile another complaint.“These …