NEW YORK — The expulsion of George Santos from Congress on Friday swept away one major political headache for Republicans, but it immediately set the stage for another: The party will have to defend his vulnerable seat in a special election early next year. The race in New York is expected to be one of the most high-profile and expensive off-year House contests in decades. It has the potential to further shrink Republicans’ paper-thin majority and offer a preview of the broader battle for House