DENVER — Pot may be legal in Colorado, but you can still be fired for using it. Brandon Coats, a quadriplegic medical marijuana patient who was fired by the Dish Network after failing a drug test more than four years ago, said he still can’t find steady work because employers are wary of his off-duty smoking. In a case being closely watched around the country, Colorado’s Supreme Court today will hear arguments in Coats’ case, which could have big implications for pot smokers in the first …