LONDON — A British judge on Monday rejected the United States’ request to extradite WikiLeaks founder Julian Assange to face espionage charges over the publication of secret U.S. documents a decade ago, saying he was likely to kill himself if held under harsh U.S. prison conditions.In a mixed ruling for Assange and his supporters, District Judge Vanessa Baraitser rejected defense arguments that the 49-year-old Australian faces a politically motivated American prosecution that rides roughshod over free-speech protections …