Two juvenile detainees suing Cook County for placing them in lockdown to film the TV show “Empire” will have to pursue their lawsuit alone for now after Chief U.S. District Judge Rebecca R. Pallmeyer denied them class status.Pallmeyer’s order, issued Thursday, found the proposed class was too broadly defined.The plaintiffs, identified only as T.S. and Q.B., sued alleging the Cook County Juvenile Temporary Detention Center let the 20th Century Fox studio shoot scenes across 14 days in the summer of 2015 …