Function headless_lms_models::user_exercise_states::update_reviewing_stage

pub async fn update_reviewing_stage(
    conn: &mut PgConnection,
    user_id: Uuid,
    course_instance_or_exam_id: CourseInstanceOrExamId,
    exercise_id: Uuid,
    new_reviewing_stage: ReviewingStage
) -> ModelResult<UserExerciseState>