“Dune 3” jumps 17 years into the future—Paul and Chani are no longer aligned, war is on the horizon, and Robert Pattinson enters the saga as a shape-shifting wildcard. The desert just got even stranger. “Dune: Part Three,” inspired by Frank Herbert’s “Dune: Messiah,” tells the story of what happens after Paul — the warrior prince and chosen one — defeats the Harkonnens and becomes Emperor, embracing…