By Guy Faulconbridge and Yew Lun Tian LONDON/BEIJING (Reuters) – Xi Jinping will leave China for the first time in more than two years for a trip this week to Central Asia where he will meet Russia’s Vladimir Putin, just a month before he is set to cement his place as the most powerful Chinese leader since Mao Zedong. The trip, Xi’s first abroad since the start of the COVID-19 pandemic, shows he is confident about both his grip on power as he heads for a third term in office and about his role as a world leader at a time of renewed great power friction. Against a backdrop of Russia’s confronta…