Justin Bieber wrote “Los Vegas” instead of “Las Vegas” with a yellow marker as he was lowered from the ceiling inside a clear glass cube Friday night at the start of his sold-out “Purpose World Tour” stop at MGM Grand Garden Arena. Spelling error aside, the Canadian superstar singer, who turned 22 on March 1, pulled out all the stops in his 90-minute spectacle that featured Bieber in fine voice acoustically and uptempo and in even finer form dancing with his onstage crew.