By Ewan Murray Pre-season friendlies can often be a drab and testing watch but there are always silver linings. For Liverpool supporters this year, there is the chance to get a first look at Arne Slot’s tactical setup with the Dutch coach succeeding Jurgen Klopp in the dugout. But, of course, there is also the opportunity to see some of the club’s brightest young academy stars in action. At Anfield, there are plenty of those, but one that has caught the eye most is 17-year-old Trey Nyoni. The midfielder was exceptional during Liverpool’s recent 1-0 friendly victory over Real Betis in the Unite…