fix: disambiguate WP users vs. guest authors with same ID

[dkoo]

All Submissions:

• Have you followed the Newspack Contributing guideline?
• Does your code follow the WordPress' coding standards and VIP Go coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Accounts for a previously unhandled edge case where a CAP guest author and a WP user might have the same numeric ID in the DB. In this case, master will always choose the guest author over the WP user because we can't tell which type of author to fetch with only the ID.

This PR fixes the above issue by storing a new block attribute isGuestAuthor as part of the Author Profile block. If this is true (the default), the block's behavior will behave as it currently does (search guest authors first, and if none found, fall back to WP users). If it's false, it will only search WP users. This ensures that if a WP user is chosen which has the same ID as a CAP guest author, the WP user will be displayed in the editor and the front-end.

Note that this doesn't fix pre-existing instances of the Author Profile block affected by this issue, as there is no way to disambiguate the numeric IDs without the new isGuestAuthor attribute. These blocks will need to be manually rebuilt in the editor.

This PR also standardizes REST API parameters as snake case and properly lists and sanitizes all possible param values in the REST route registration. Otherwise, the Author List and Author Profile behavior should remain the same.

Closes #1134.

How to test the changes in this Pull Request:

1. On a brand new site with no posts and Co-Authors Plus and Newspack Blocks (current release) installed, create enough WP users and CAP guest authors so that you have at least one guest author with the same ID as a WP user. Hint: if you run wp site empty --yes at CLI and then create a guest author, the ID will be 1 and the same as the main admin user.
2. Create some Author List blocks with various settings (for testing after the plugin upgrade).
3. Create an Author Profile block and attempt to select the WP user with an ID that overlaps with a guest author. Observe that the guest author is displayed in the editor and on the front-end despite your selection.
4. Install the Blocks plugin from this branch.
5. Recreate the Author Profile block in step 3 and confirm that it now displays the correct WP user in the editor and on the front-end.
6. Confirm that the Author List blocks still behave as before, and that both Author Profile and Author List blocks continue to behave as expected.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran tests with your changes locally?

[adekbadek]

This fixes the issue. Noting that the Author List block should also be updated – added #1150

[matticbot]

🎉 This PR is included in version 1.52.0-alpha.1 🎉

The release is available on:

• npm package (@alpha dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[matticbot]

🎉 This PR is included in version 1.52.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀