The state Court of Appeal has thrown out a $150,000 jury award to a woman who sued the city of Los Angeles after she was raped in her Northridge home by an on-duty Los Angeles police sergeant. In a 2-1 decision, the court found that Sgt. Leigh B. Schroyer was not acting within the course and scope of his police job when the rape occurred in October, 1981, and that the city, therefore, should not be accountable for his actions. Schroyer, who resigned shortly after the rape, was convicted in June, 1982. He served 18 months in prison. Following the criminal proceedings, the victim, a 33-year-old mother of two, sued the city and Schroyer, claiming that the assault caused her to acquire a drinking problem, gain 75 pounds, lose her sex drive and become a recluse.