At Sardi’s, the show must go on. The legendary theater district restaurant known for its storied celebrity caricature collection has found a new owner in theater behemoth the Shubert Organization, The Post has learned. The iconic 44th Street site will close temporarily over the summer for renovations, 71-year-old owner Max Klimavicius told The Post. Shubert reps have already vowed to preserve the century-old charm of the Great White Way’s watering hole — including its more than 1,200 quirky