Alibaba Group Holding Ltd. agreed to sell its shares in Sun Art Retail Group Ltd. to private equity firm DCP Capital, unloading another high-profile physical commerce asset to focus on its core online business.China’s e-commerce pioneer said it could receive gross proceeds of up to HK$12.3 billion ($1.6 billion) from selling its more than 70% holding in the chain of Costco-like hypermart stores. That’s significantly less than the $3.6 billion Alibaba paid just to double its stake in Sun Art in 2...