Flex: modify stop_without_stop_time to exclude stops associated with a used location_group

[emmambd]

Describe the problem

Based on the acceptance test changes from #1834 (comment), there are changes in fixed stop demand responsive services where a stop_id will not be referenced explicitly in stop_times.txt and therefore would generate the stop_without_stop_time warning, even though the stop_id is technically used.

Proposed solution

Create an exception for this rule:

If there's a location_group_id referenced in stop_times.txt, go through the original location_group file and check all the stops associated with that id. If a stop exists in the location_group that is being used in stop_times, don't trigger the warning.

Alternatives you've considered

No response

Additional context

No response

[qcdyx]

stop_id can be referenced directly or indirectly
check if stop_id is referenced
if not, check if location_group_id is referenced
if stop is a part of location_group, it can be referenced
in one entry, you can reference only 1

[qcdyx]

Hey @emmambd could you provide a test feed please? I tried some datasets based on #1834 (comment), no luck.