By David Lawder WASHINGTON (Reuters) -U.S. President Joe Biden’s warning of “consequences” for any aid China may give to Russia’s Ukraine war effort aims to force Chinese President Xi Jinping to choose a longstanding lucrative trade relationship with the West over a growing strategic partnership with Moscow. Based on trade flows alone, both China and the United States have a lot at stake after Biden’s nearly two-hour video call with Xi on Friday, with the White House confirming that sanctions on Beijing were an option. Despite growing trade ties to Southeast Asia and an economy that is less de…