CHARLOTTE, N.C. — Just when the Charlotte Hornets welcomed a much-needed face with open arms, they watched their most exciting player exit with an injury in the second half. LaMelo Ball sprained his left ankle in the third quarter and didn’t return, putting a somber damper on the Hornets’ final preseason home tuneup on Monday night. A 116-107 loss to Washington at Spectrum Center seemed inconsequential, though, with everyone wanting to know more about the fate of the Hornets’ All-Star point guard. Ball came up gimpy during a drive to the basket when Wizards forward Anthony Gill stepped on his …