Describe the problem

We want to be able to support Flex as a part of #1721, we need to add a schema for the new file location_groups.txt and update the stop times schema to include new fields and modify stop_id from required to conditionally required.

Proposed solution

New schema. Test by checking if:

• foreign_key_violation is triggered when location_group_id is defined in stop_times.txt but not in location_groups.txt. Test with modified-flex-feed-4226672-missing.zip. I removed location_group_id 4226672 from location_groups.txt in https://data.trilliumtransit.com/gtfs/islandtransit-wa-us/islandtransit-wa-us--flex-v2-TEST.zip to test this.

• Check that missing_required_field no longer triggers when there's no stop_id in stop_times.txt AND a present id in locations.geojson OR location_group_id in location_groups.txt. Check with https://data.trilliumtransit.com/gtfs/islandtransit-wa-us/islandtransit-wa-us--flex-v2-TEST.zip

• Run performance tests on the implications of adding/checking additional fields in stop_times.txt

• Update notice in locations.geojson POC phase2: End-to-end partial support of json data #1810 to reflect requirements here for duplicate_geography_id

Alternatives you've considered

No response

Additional context

No response