LOS ANGELES — A Los Angeles teachers union leader hinted of a possible resumption of contract bargaining Wednesday as striking educators in the second largest U.S. school district walked picket lines outside hundreds of schools for a third day. “We’ll have more information for you later in the day about the bargaining table and when we’re getting back to that bargaining table,” United Teachers Los Angeles President Alex Caputo-Pearl told teachers rallying in the rain outside a high school. Caputo-Pearl said the union had “engaged” Mayor Eric Garcetti to help in the dispute that prompted administrators to staff classroom with substitute teachers, but he provided no further details.