Janet Jackson went “full circle” to debut her Las Vegas residency, “Metamorphosis,” Friday at Park Theater at Park MGM. The singer, who just turned 53, told the crowd, “I made my debut when I was 7 years old, right here in Las Vegas. And the beautiful thing about it is it was at the MGM Grand Hotel with my brothers and sisters. It’s so amazing how things come full circle . . . so beautiful.”...