Chris Pratt may be a loyal star of two of the biggest movie franchises of the moment, between Marvel and “Jurassic World,” but even he craves something original sometimes. It’s at least part of the reason why he found himself drawn to what would become “The Tomorrow War,” which debuts Friday on Amazon Prime Video. This story about a future war that recruits an army from the past wasn’t based on a comic book or a toy or a brand. And he signed on not only to star as a father separated from his family by a draft, but also executive produce for the first time in his career.