Unlike lasagna, Garfield the cat lacks layers. He loves Italian food, hates Mondays and is neutral toward his owner, Jon, and canine sidekick, Odie. This simplicity has sustained Garfield’s 46-year career as the world’s most widely syndicated comic strip, plus a side hustle that’s slapped his striped rump on coffee cups, car windshields, slippers, sofas, lava lamps, fish tanks, landline phones and, now, his third theatrical feature, “The Garfield Movie,” which takes the simplest of ingredients and somehow gets every one wrong.