By Samuel Meade UFC chief Dana White has joked that Eddie Hearn’s hopes of landing the first fight at The Sphere “ain’t happening”. Las Vegas’ latest venue has just opened and there is a battle between the combat sports to have the first event there. Eddie Hearn and Matchroom are eyeing a rematch between Katie Taylor and Amanda Serrano. Hearn claims a bout between the pair is “an obvious fight for them both, the first one was a classic.” The Sphere has been touted as the venue for the fight but White and UFC have other plans. They just completed a historic night at UFC 300 and the president ha…