Revisions controller: fix author and date fields

[ramonjd]

What, why, how?!

Correcting a mistake I made in #49974: we need the author, date and other details from the revision item not the parent

Testing Instructions

Run the tests!

npm run test:unit:php -- --filter Gutenberg_REST_Global_Styles_Revisions_Controller_Test

For bonus points, create another admin user and save some global styles changes.

Check that the revision items reflect the revision author's details. You can grab them in the console:

await wp.apiFetch( { url: `/index.php?rest_route=%2Fwp%2Fv2%2Fglobal-styles%2F${ wp.data.select('core').__experimentalGetCurrentGlobalStylesId() }%2Frevisions&_locale=user` } );

[github-actions]

Flaky tests detected in 931affd.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/4816248200
📝 Reported issues:

• [Flaky Test] shouldn't conflict with server-side autosave #35176 in specs/editor/various/autosave.test.js

[andrewserong]

Great catch, thanks for the quick fix! How did we miss this earlier 😅

Before	After

LGTM! ✨

[andrewserong]

For bonus points, create another admin user and save some global styles changes.

I decided I'd go for the bonus points 😄

Multiple users is working nicely, too:

[ramonjd]

How did we miss this earlier

Thank you for the use of the first person plural, but it's okay in this case to say "How did YOU, @ramonjd, miss this earlier!?" 🤦 haha

Thanks for testing 🙇