Atlantic City’s main casino workers union and the New Jersey attorney general on Monday asked a judge to dismiss a lawsuit brought by a different union that seeks to ban smoking at the city’s nine casinos. Local 54 of the Unite Here union said in a filing in state Superior Court that a third of the 10,000 workers it represents would be at risk of losing their jobs and the means to support their families if smoking were banned. Currently, smoking is allowed on 25% of the casino floor. But those areas are not contiguous, and the practical effect is that secondhand smoke is present in varying deg…