By Alexandra Alper, Michael Martina and Steve Holland WASHINGTON (Reuters) -U.S. President Joe Biden and China’s leader Xi Jinping are expected to talk on Thursday, a source familiar with the planning said, amid tensions over Taiwan and Russia’s invasion of Ukraine. White House national security spokesperson John Kirby told reporters on Tuesday that managing economic competition between the two countries would also be a focus of the call. It will be the fifth call between the leaders, and comes as China has delivered heightened warnings to the Biden administration about a possible visit by U.S…