Is Jean-Yves Thibaudet the classical pianist being overshadowed by Thibaudet the media sensation? His recent recordings have included arrangements of opera melodies, excerpts of film soundtracks, jazz, as well as more classical fare. His concert attire is designed by Vivienne Westwood, and he has homes in Paris and, of course, Los Angeles. In a recital sponsored by Washington Performing Arts Society Saturday afternoon at the Kennedy Center, Thibaudet had the chance to show Washingtonians that…