No one knows where luck comes from, because luck doesn’t come from anywhere, and attempting to identify its source is like asking where happiness is made or why is there love. Hopefully the baffling “Luck,” in all its inscrutability and forced whimsy, stops filmmakers from attempting to take on those other subjects. This impossibly complicated animated fantasy undoubtedly started in a writer’s room somewhere with screenwriters Kiel Murray, Jonathan Aibel and Glenn Berger trying to explain the origins of luck. Director Peggy Holmes (the “Little Mermaid” prequel “Ariel’s Beginning”) then plunges…