The toon trio that stars in TV’s “Steven Spielberg Presents Animaniacs” will make it to the bigscreen in a short that will precede Warner Bros.’“Hans Christian Andersen’s Thumbelina,” scheduled for a March 30 release. “Animaniacs” appears weekdays on the Fox Children’s Network. It is produced by Amblin Entertainment in association with Warner Bros. Animation. The four-minute-and-50-second short, “I’m Mad,” is a look at the back-seat bickering among siblings during a car trip.