Alibaba Group Holding Ltd. posted the slowest revenue growth for the second straight quarter since it went public in 2014, and the Chinese e-commerce giant said the challenges of Covid-19 outbreaks are seriously undermining its operations across China. The impact of Covid-19 restrictions has added to the already heavy financial toll on the company from regulatory measures and economic slowdown. Alibaba said it has been broadly impacted by supply chain and logistics disruptions since mid-March — when a spate of infections with the Omicron variant of the coronavirus hit China. It said cities with new Covid-19 cases accounted for more…