By Mathieu Rosemain PARIS (Reuters) -French media group Banijay will go public through a merger with a blank-check acquisition firm backed by billionaire Bernard Arnault in a deal worth more than 4 billion euros ($4.21 billion), an executive at its parent company said on Tuesday. The production house behind global television hits such as “The Voice”, “Black Mirror,” “The Kardashians” and “Master Chef” will be part of a listed entity, dubbed FL Entertainment, whose first day of listing will be on July 1, the executive, Francois Riahi, said. The deal gives FL Entertainment an enterprise value of…