She is best known to the public as TV's crew-cut, uniformed Hotel employee, so Shari Belafonte-Harper, 31, likes to compensate for that contained image the rest of the time. ''You go out so many times, you sort of feel like, 'What can I do that will make me a little different?'' she says. At a recent awards ceremony, she turned heads with a glittering turquoise outfit, complete with matching wig. This month at a celebrity ''epicurean gala'' in Los Angeles benefiting cancer research, she fried up a batch of her mother-in-law's sesame chicken, complete with ''beer, spices and everything that is bad for you.'' Since she was freshly shorn for a fashion-modeling assignment, she also took the occasion to show off another of her many wigs, along with a crocheted headdress dripping with beads and feathers. TV viewers will see the more conventional Belafonte-Harper again next fall when she returns to her Hotel information desk. Maybe if fans complain, stern James Brolin, who runs the hostelry, will let her cut loose. Why not that headdress and feathers to liven up the lobby?