By Rory Carroll LOS ANGELES, June 13 (Reuters) - Iran open their World Cup Group G campaign against New Zealand in Los Angeles on Monday in a match shaped as much by events off the pitch as by the ambitions of two teams seeking a long-awaited breakthrough. The fixture will be played against the backdrop of the U.S. war with Iran and in a region home to the largest Iranian community outside the country, adding a charged atmosphere to a contest between two nations who have never met at the World Cup.