fix: set transfer from and to stop ids as conditional required fields

[davidgamez]

Summary:

This PR aligns the validator response with the specification on the transfers.txt from and to stop IDs. The specification marks these fields as required for all records except those with a transfer_type of 4 or 5.

Closes #1621

Expected behavior:

For transfers.txt records with transfer types 4 and 5(in seat transfer types), the missing required field is not triggered.

Please make sure these boxes are checked before submitting your pull request - thanks!

• [x] Run the unit tests with gradle test to make sure you didn't break anything
• [ ] Add or update any needed documentation to the repo
• [x] Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• [x] Linked all relevant issues
• [ ] Include screenshot(s) showing how this pull request works and fixes the issue(s)

[github-actions[bot]]

✅ Rule acceptance tests passed. New Errors: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. Dropped Errors: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. New Warnings: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. Dropped Warnings: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. 0 out of 1523 sources (~0 %) are corrupted. Commit: 7e6ac6983b976ec380f74fae5079452e0f4deb19 Download the full acceptance test report here (report will disappear after 90 days). ✅ Rule acceptance tests passed.

[github-actions[bot]]

✅ Rule acceptance tests passed. New Errors: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. Dropped Errors: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. New Warnings: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. Dropped Warnings: 0 out of 1523 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%. 0 out of 1523 sources (~0 %) are corrupted. Commit: cb457647a0dc453ff25ea4cbda5473b70c486ee9 Download the full acceptance test report here (report will disappear after 90 days). ✅ Rule acceptance tests passed.