A Vital Interview - Philip Abbott, as probation officer John Collier, interviews a young first offender in the opening case on the NBC-TV Network's new daytime drama series, "The House on High Street." The program, which is based on actual cases from the files of Domestic Relations Courts, Mondays. It is Collier's job, on assignment by a judge, to seek out and question anyone who might be able to offer a clue to the defendant's behavior.