There’s something strangely Disney-like about Arena Stage’s production of She Loves Me. Is it the candy-colored sets? The cartoonish dancing? The opening song, “Good Morning, Good Day,” which calls to mind Beauty and the Beast’s “Bonjour” number? Or maybe it’s just that leading lady Brynn O’Malley seems to have taken her recent performance as Belle in Broadway’s Beauty and the Beast and transplanted it in D.C.? She Loves Me, a classic, romantic musical adored by…