LONDON — Block, the payments company owned by tech billionaire Jack Dorsey has launched its corporate card service in the U.K. in a bid to deepen its expansion into the country and take on big incumbents like American Express.The firm's business-focused payments arm, Square, told CNBC that it opened registrations for its Square Card product in Britain late Wednesday, marking the first time Block has expanded its business card offering outside North America, where it first launched in 2019.Currently availabl ...