“Sopranos” creator David Chase breaks his omerta on the controversial final scene of this landmark series and the possibility of a movie version in the copious new extras included in the limited-edition giftset of the entire 86-episode masterpiece, out Tuesday from HBO. I have a preview in today’s Post. Chase seems to hint that indeed, the Sopranos did get whacked at the diner. “A lot of people weren’t going to be happy unless Tony’s brains were splattered on the table,” he says. “But did we really want to see that?” On the other hand, Chase isn’t flatly ruling out the much-rumored “Sopranos” feature film. “If somebody has a great idea for a ‘Sopranos’ movie and everybody want to do it, we’d do it,” he says. Maybe a prequel?