A federal judge declined to throw out a claim accusing an investigator for the DuPage County State’s Attorney’s Office of invading the privacy of a psychotherapist’s patients by seizing their files.In a written opinion last week, Chief U.S. District Judge Ruben Castillo did not rule on the merits of the allegations included in the proposed class-action lawsuit David Callahan and Heine Heininger filed against investigator Cheryl York and other defendants.But Castillo held Callahan and Heininger had stated …