SPRINGFIELD — The sitting mayor of a Metro East city should be removed from the ballot this year, the state’s high court ruled Monday. In a unanimous decision, the Illinois Supreme Court disagreed with two lower courts and an election board, which said East St. Louis Mayor Alvin Parks Jr. should stay on the ballot despite a shortage of voter signatures because of a “substantial compliance” theory. Parks’ nominating petitions were contested by an opponent in the race, Emeka Jackson-Hicks …