LOS ANGELES — The music publishing company that has been collecting royalties on the song “Happy Birthday To You” for years does not hold a valid copyright on the lyrics to the tune that is one of the mostly widely sung in the world, a federal judge ruled Tuesday.U.S. District Judge George H. King determined the song’s original copyright, obtained by the Clayton F. Summy Co. from the song’s writers, only covered specific piano arrangements of the song and not its lyrics.The basic tune of the …