NEW YORK — Former New York City Mayor Bill de Blasio, struggling mightily in recent opinion polls, pulled the plug on his run for Congress on Tuesday, more than a month out from the vote in the Democratic primary. In a video he published on Twitter, de Blasio acknowledged that voters in his district are “looking for another option.” The concession came as a humbling blow for the 61-year-old politician, who once fashioned himself as the future of the progressive movement, won two terms at City Hall and even ran for president. He entered the race for New York’s 10th Congressional District in May…