Check if the post is distributed, and if it is apply the author filter

[ggutenberg]

Description of the Change

If an author ID is specified in a call to get_the_author_meta(), instead of returning the specified author blindly, we are also checking the post itself and whether or not it was distributed. If it was, we apply the get_the_author_display_name and get_the_author_user_url filters as usual.

Closes #1015

How to test the Change

Make sure you're using a theme that supports the block editor for this like Twenty Twenty-Two, as the Classic editor themes don't have an issue.

1. Create a post on the source site.
2. Distribute it to the target site.
3. In Distributor settings, make sure that Override Author Byline is checked.
4. View the distributed post on your site. Note that it displays the source site as the author.
5. Uncheck Override Author Byline in the Distributor settings.
6. View the distributed post on your site. Note that it now displays the target site's author.

Changelog Entry

Fixed - Author override fails in the block theme author block.

Credits

Props @ggutenberg

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[peterwilsoncc]

Tests well, thanks Garth.

I've made one suggestion inline.

[peterwilsoncc]

LGMT, checked on a variety of block and classic themes.