Wellesley’s superintendent of schools apologized today after Wellesley Middle School students were allowed to pray at an Islamic mosque during a May field trip. "It was not the intent for students to be able to participate in any of the religious practices,” Superintendent Bella Wong wrote in a letter being sent to parents later today. “I extend my sincere apologies for the error that occurred and regret the offense it may have caused.” Wong said the field trip to the Roxbury-based Islamic Society of Boston Cultural Center — which faced opposition during its construction — was part of a social...