Zohran Mamdani said he would discourage the use of the slogan “globalize the intifada” in a roughly hourlong meeting with some of New York City’s most powerful executives on Tuesday, seeking to defuse an issue that has prompted a backlash from the business community and beyond. Mamdani, the Democratic nominee for New York City mayor, was grilled by a room of 100-plus executives at an event hosted by the Partnership for New York City, an influential business group. The audience included finance and real-estate executives, high-powered lawyers and a handful of billionaires.