Apple Inc. will face questions from European Union regulators over accusations it barred Epic Games Inc. from opening its own app store for iPhone customers in Europe — the latest twist in a long-running fight between the two companies. Epic said that Apple had terminated its developer account on Wednesday, preventing the gaming company from bringing Fortnite and the Epic Games Store to Apple’s iOS devices in the EU. Epic chief executive officer, Tim Sweeney, accused Apple of violating the EU’...