Function headless_lms_models::exercise_service_info::get_course_material_service_info_by_exercise_type

pub async fn get_course_material_service_info_by_exercise_type(
    conn: &mut PgConnection,
    exercise_type: &str,
    fetch_service_info: impl Fn(Url) -> BoxFuture<'static, ModelResult<ExerciseServiceInfoApi>>
) -> ModelResult<Option<CourseMaterialExerciseServiceInfo>>

Returns service info meant for the course material. If no service info is found and fetching it fails, we return None to indicate that the service info is unavailable.