Making a movie with your own child is perilous enough at a time when the media, which is stuffed with them, has decided that “nepo babies” are the latest blight on the eco-system of filmmaking. It’s even more of a risk when your private life has been splashed all over the tabloids, and the facts of that controversy — man leaves wife and kids to start a new family with a younger woman — are a key part of that movie. But whether or not Ewan McGregor and his daughter Clara saw the film as a chance for family therapy, or whether they even thought about these things at all, Emma Westenberg’s affecting, slow-burn debut leaves all that kind of real-world baggage firmly at the door.