LONDON — The U.S. government is scheduled to ask Britain’s High Court on Wednesday to overturn a judge’s decision that WikiLeaks founder Julian Assange should not be sent to the United States to face espionage charges. In January, a lower court judge refused an American request to extradite Assange on spying charges over WikiLeaks’ publication of secret military documents a decade ago. District Judge Vanessa Baraitser denied extradition on health grounds, saying Assange was likely to kill himself if held under harsh U.S.