Four years ago, Paul Vallas finished toward the bottom of the pack in a crowded race for Chicago mayor. Trying again on Tuesday, focused this time on crime, he was the top vote getter, toppling the incumbent mayor and advancing to an April runoff to lead one of the country’s largest cities.His new campaign message, concentrated on citizens’ safety and support for the police, resonated with voters in this Democratic city in a way it might not have before the COVID-19 pandemic, when rates of violent crime spiked.“Public …