Created by the Canadian company WowWee, the Fingerling has been anointed one of this year’s hot toys for the holidays, a designation that most toymakers only dream of achieving. For decades, there has always been a must-have holiday toy — Cabbage Patch Kids, Beanie Babies, a Tickle Me Elmo doll. Parents drive long distances to scour stores for the one item in short supply at exactly the moment when everyone wants it.