It’s not Rachmaninoff’s fault that songwriters swiped his best hooks—like the sighing and songlike slow movement of his Second Symphony—and turned them into soft-rock earworms. If you’re going to steal, you might as well steal from the best. Conductor Robin Ticciati and debuting pianist Francesco Piemontesi make their case for Beethoven’s alluringly strange, strangely alluring Piano Concerto No. 4.