The U.S. soldier detained in Russia earlier this month confessed to charges of theft after he was accused of stealing money from his girlfriend, Russian state media claims. Army Staff Sgt. Gordon D. Black was arrested May 6 in Vladivostok. Black, 34, “admitted guilt and is cooperating with the investigation,” a Russian law enforcement representative said, TASS reported Thursday. Black — a married father in the middle of a divorce — was stationed in South Korea and was traveling to his next duty station in the United States, when he made a stop in Russia to visit his girlfriend, identified as 3…