Manchester United’s time for trial and error is over and when they next take the field, a trophy will be at stake and against them will be their city neighbours. The Community Shield final is on August 10 and after a pre-season that gave some hope, some fear, and a lot of learnings, the time to put it to use will arrive soon. The injuries will be the biggest talking point, alongside the returns of many internationals who have reported to Carrington after their extended holiday. Therefore, it will be extremely difficult to predict what team Erik ten Hag selects for that game because even though…