### Description
This is it! This PR enables the Metadata API for remote relationships from remote schemas, adds tests, ~~adds documentation~~, adds an entry to the Changelog. This is the release PR that enables the feature.
### Checklist
- [ ] Tests:
- [x] RS-to-Postgres (high level)
- [x] RS-to-RS (high level)
- [x] From RS specifically (testing for edge cases)
- [x] Metadata API tests
- [ ] Unit testing the actual engine?
- [x] Changelog entry
- [ ] Documentation?
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3974
Co-authored-by: Vamshi Surabhi <6562944+0x777@users.noreply.github.com>
Co-authored-by: Vishnu Bharathi <4211715+scriptnull@users.noreply.github.com>
Co-authored-by: jkachmar <8461423+jkachmar@users.noreply.github.com>
GitOrigin-RevId: c9aebf12e6eebef8d264ea831a327b968d4be9d2
