Daniel Zhang, the departing chief executive and chairman of the Chinese tech giant Alibaba, has stepped down as head of the tech company’s cloud division, a position he held for mere months. The company announced in June that Mr. Zhang, would give up the chairman role this month to Joseph Tsai, a co-founder of Alibaba, and that Eddie Yongming Wu, another founder, would became the chief executive. But Mr. Zhang had been widely expected to continue to lead Alibaba’s cloud computing division, a position he assumed in March as part…