It’s not everyday that The Sugarhill Gang, Sisqo, and Dru Hill are hanging around a party at a house in D.C.’s Chinatown. The artists were in town yesterday to lobby, not for thongs or hip hopping to hippie, but for the Performance Rights Act, which would give terrestrial broadcast royalties to performers of songs. Currently songwriters and composers get royalties. The party, held in an ultramodern house, was organized by SoundExchange, a music industry non-profit…