The county Board of Supervisors, ending a controversy some felt was motivated by anti-Semitism, has granted the Pasadena Jewish Temple a conditional use permit to expand a day school operating on its property in Altadena. The board unanimously agreed to allow the B'nai Simcha day school to expand from its present 60 students to 80 students and to add fifth and sixth grades. The decision requires the temple to construct a barrier along the school's playground to block noise and prohibits use of the pool and play areas before 9 a.m. Neighbors of the day school at 1434 N. Altadena Drive had complained that the expansion would detract from the aesthetics of the area and cause traffic and noise problems. Officials of the day school, which was established io 1983, said the zoning requirement limiting its size punishes students who would be forced to transfer to another elementary school after the fourth grade. Such transfers would have taken place for the first time in September.