Alfonso Ribeiro is waltzing right in as the new co-host of “Dancing with the Stars.” The Bronx, New York-born actor, whose eccentric dance moves as Carlton on “The Fresh Prince of Bel-Air” helped make him a fan favorite, will host the Disney+ competition show’s 31st season alongside returning emcee Tyra Banks, the network announced Thursday. Ribeiro, 50, won the 19th season of “Dancing with the Stars” in 2014 as the partner of professional Witney Carson. “‘Dancing with the Stars’ has been such an important part of my life for so many years, and I am ecstatic to officially re-join this tight-kn…