fix: new shared stops error types

[miles-grant-ibigroup]

Checklist

• [ ] Appropriate branch selected (all PRs must first be merged to dev before they can be merged to master)
• [ ] Any modified or new methods or classes have helpful JavaDoc and code is thoroughly commented
• [ ] The description lists all applicable issues this PR seeks to resolve
• [ ] The description lists any configuration setting(s) that differ from the default settings
• [ ] All tests and CI builds passing
• [ ] The description lists all relevant PRs included in this release (remove this if not merging to master)
• [ ] Code coverage does not significantly worsen (ideally it improves) (remove this if not merging to master)

Description

Unfortunately the superior approach from #390 did not work, and so we must now instead add shared stops errors to gtfs-lib explicitly.