PHNOM PENH, Cambodia—A gold-hued skyscraper is rising above the traffic-clogged streets of the capital city on the Mekong River.The skyscraper is being built by a company under sanctions by the U.S. Treasury Department for its alleged connection to one of hundreds of scam operations that have cropped up across CambodiaThe building is already Cambodia’s tallest structure—and a monument to the spoils generated by transnational cybergangs that have stolen billions of dollars from unsuspecting Americans and others worldwide.The skyscraper is being built by a company under sanctions by the U.S. Treasury Department for its alleged connection to one of hundreds of…