arrested by cops in Louisiana for refusing to return to their mother as part of a bitter custody battle were strip searched before being placed alone in separate jail cells for two nights, their friend and neighbor told The Post.Brother and sister duo Kadan, 15, and Brooklyn Rockett, 13, — who wowed Simon Cowell in the “AGT” semifinals back in 2016 — were unable to pull a Houdini and escape what they told friends was a scary stay in a roach-infested juvenile detention center near where their