By Michael Pina Few saw the Grizzlies star rising to an MVP level so fast because he didn’t want anyone to know: He worked in the dark so he could shine like never before. Ja Morant looks comfortable. It’s January, about 45 minutes before tip-off at FedExForum, and a throng of fans has arrived early to watch this NBA season’s most electric performer amble through a series of jump shots. For Morant, the spotlight burns brighter every night. But here, wearing a sleeveless, white Grizzlies hoodie, he seems oblivious to the attention, as if he was jogging around the blacktop in his backyard on a l…