Apple Inc. is winding down a long-running project to design and develop its own smartwatch displays, putting an end to another pricey research and development initiative.In recent weeks, the company has ceased an in-house effort to create screens with microLED technology, according to people with knowledge of the matter. The displays, which featured brighter and more vibrant visuals, would have been added to a future version of the Apple Watch — before potentially going into other products....