KOSICE/VYSNE NEMECKE, Slovakia (Reuters) -U.S. first lady Jill Biden met Ukrainian refugees in eastern Slovakia on Sunday, the last full day of her tour of Romania and Slovakia to visit U.S. servicemen deployed there and women and children who fled Russia’s invasion of Ukraine. Biden spoke to families, volunteers and local authority workers at a refugee centre in the eastern Slovak city of Kosice, one of the main transit points for over 400,000 Ukrainian refugees who have crossed the border to Slovakia. The United Nations says 5.8 million people in total have fled Ukraine since Russia started …