Huawei Technologies Co. is considering taking a cut of in-app purchases on its Harmony mobile operating system, underscoring its growing confidence in competing with Apple Inc. in the world’s largest smartphone arena. The Shenzhen-based company is weighing a commission lower than the typical 30% cut that Apple and Alphabet Inc.’s Google take for payments made via their mobile stores for things like apps, games, movies and music subscriptions, according to people familiar with the matter. Huawei ...