WASHINGTON — Democrats can’t use their $3.5 trillion package bolstering social and climate programs for their plan to give millions of immigrants a chance to become citizens, the Senate’s parliamentarian said late Sunday, a crushing blow to what was the party’s clearest pathway in years to attaining that long-sought goal.The decision by Elizabeth MacDonough, the Senate’s nonpartisan interpreter of its often enigmatic rules, is a damaging and disheartening setback for President Joe Biden, congressional Democrats and their …