Adam B. Vary Senior Entertainment Writer SPOILER ALERT: This story discusses major plot developments in “The Last Generation,” the series finale of “Star Trek: Picard,” currently streaming on Paramount+. The last time the cast of “Star Trek: The Next Generation” cast performed together on screen — in 2002’s “Star Trek: Nemesis” — ended with a sour one-two punch: the sudden death of Data (Brent Spiner) and the financial failure of the film, which caused Paramount to stop making movies with the cast. Effectively, after a brilliantly successful seven-season run on TV, “The Next Generation” had been canceled from movie theaters. Two decades later, when Terry Matalas was tapped to executive produce the final season of “Star Trek: Picard,” the lifelong “Trek” fan knew that he not only wanted to bring back the full “TNG” cast, but provide them with the send-off they had never received.