Microsoft has backed “Fortnite” video game maker Epic Games in its legal battle with Apple – alleging in a new court filing that the Tim Cook-led tech giant has “stymied” its own efforts to create an Xbox mobile store.In an amicus brief filed late Tuesday in California federal court, Microsoft said Apple’s restrictions had prevented it from “launching its own online store” and argued the injunction against Apple should be enforced even during the appeal process.“The district court’s injunction allows Apple ...