NEW YORK — A judge correctly struck down a new Department of Homeland Security rule that went into effect earlier this year denying green cards to legal immigrants who use Medicaid, food stamps and other forms of public assistance, an appeals court said Tuesday.The 2nd U.S. Circuit Court of Appeals upheld an October ruling by Judge George B. Daniels but only let it apply to New York, Vermont and Connecticut, conforming with a U.S. Supreme Court ruling that let the rule take effect in February.The appeals court said the …