Introduce tenup-content-connect-update-relationships-order action

[ocean90]

Description of the Change

Introduces a new action to let extenders run logic after order has been updated.

Closes #114

How to test the Change

Changelog Entry

Added - tenup-content-connect-update-relationships-order action for developers.

Credits

Props @ocean90

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.

[s3rgiosan]

Thanks @ocean90 pulling this into the 2.0.0 release (current develop). Rebased your two commits onto develop on feature/tenup-content-connect-update-relationships-order #123 , with your authorship preserved (Author: + Co-authored-by: trailer).

Small adjustments while landing it:

• Resolved a trivial whitespace conflict against develop (kept develop's alignment).
• Bumped the docblock @since from 1.7.0 → 2.0.0, since 1.7.0 never shipped.
• Made the @param $object_id doc type-agnostic — the action also fires in the user-to-post case with a user ID, not a post ID.

No behavioral changes to your implementation. Will ship as part of 2.0.0. 🙌