The Backstreet Boys are almost done being back…alright. Nick, Howie, AJ, Kevin and Brian are scheduled to wrap their ongoing ‘Millennium’ residency at Las Vegas Sphere this week. Their final four shows go down: Wednesday, Feb. 11 8 p.m. Friday, Feb. 13 8 p.m. Saturday, Feb. 14 8 p.m. Sunday, Feb. 15 8 p.m. If you’d like to be there, last-minute tickets are still available on sites like StubHub and Vivid Seats for their swan song. At the time of publication, the lowest price we could find on