This PR updates the Danger check for touching the Collab schema files to
require attestation that the database schema migrations have been
created and applied.

If there are changes to the schema files without the attestation, Danger
will fail the status check with an error:

<img width="959" height="635" alt="Screenshot 2026-06-03 at 4 58 56 PM"
src="https://github.com/user-attachments/assets/e0857137-b351-4212-a023-13a7d53f5934"
/>

When the attestation clause is present, Danger will report it as such:

<img width="901" height="333" alt="Screenshot 2026-06-03 at 4 59 45 PM"
src="https://github.com/user-attachments/assets/098b0ce4-f86e-4d41-b6af-765bc015fe6e"
/>

Release Notes:

- N/A