June 19 (Reuters) - Diplomatic niceties broke down at the United Nations on Friday when Israel's ambassador and the U.N. secretary-general's special representative for children and armed conflict became embroiled in a furious shouting match at a public hearing. At a meeting in New York to mark the International Day for the Elimination of Sexual Violence in Conflict, the Israeli envoy, Danny Danon, demanded the resignation of Pramila Patten, who produced a report that blacklisted Israel for such alleged abuses for the first time, accusing her of bias.