Randy Madden -- the former "American Idol" contestant accused of having sex with a minor -- is refusing to address the allegations ... walking right by photographers who asked him about the charges. Madden walked out of a Ventura County, California courthouse Thursday ... limping along with a cane in his right hand and holding a phone tightly against his left ear. Several paps were waiting for Madden -- who appeared on Season 8 of the hit singing competition show -- and they asked him if he had