The head of New Jersey’s largest teachers’ union is making noises about running for governor in 2025, testing the waters with a dark money group funding digital ads and a vow to fight for working class people. But right at the starting gate, Sean Spiller needs to address the many legitimate concerns about his ethics,both as mayor of Montclair, and president of the New Jersey Education Association. He could start by explaining why he is invoking the Fifth Amendment right against self-incrimination to avoid answering charges that he took health benefits in Montclair that he was not entitled to, …