NEW YORK — The brazen attack on New York City Police Department officers by a group of migrants outside a Times Square shelter prompted an immediate — and strong — backlash. The attack became a lightning rod for criticism over the already-polarizing migrant crisis in New York City, with calls for the migrants involved to be deported. But the midtown brawl was the latest in a series of violent episodes linked to migrants, many unfolding against a backdrop of increasing frustration and despair. There have been knife fights, stabbings, tussles after NYPD moped confiscations, struggles over coats …