Ensure DQ dataset checks use code

This page is a capture in the next bucket of the product backlog — a pre-sprint idea, not yet pulled into a sprint as a story.

We are still checking for Name:

-- Get the flags dataset ID (for linking images)
select id into v_flags_dataset_id
from ores.dq_datasets_tbl
where name = 'Country Flag Images'
  and subject_area_name = 'Country Flags'
  and domain_name = 'Reference Data'
  and valid_to = ores.utility_infinity_timestamp_fn();

if v_flags_dataset_id is null then
    raise exception 'Dataset not found: Country Flag Images';
end if;