A federal court jury has ruled that anticompetitive restrictions have shielded Google’s Android app store, harming software developers and smartphone users alike and upending a key tenet of a vast digital empire. The jury deliberated for just three hours before reaching a unanimous decision on Monday. The trial lasted four weeks and focused on a profitable payment scheme found in Google’s Play store. The store is the primary location where hundreds of millions of users worldwide download and install applications designed for smartphones running Google’s Android operating system. Epic Games, the maker of the popular Fortnite video game, filed a lawsuit against Google three years ago, alleging that the internet powerhouse has been abusing its power to…