Plans to create the city’s first public law school got the green light from the American Bar Association and Illinois Board of Higher Education.The state board yesterday approved the University of Illinois at Chicago’s request to acquire The John Marshall Law School. This, coupled with the approval the ABA’s Council of the Section on Legal Education and Admissions to the Bar gave late last month, clears some major — but by no means final — hurdles before the merger can go through.The ABA …