Compatibility with Index WP Users for Speed

[jffaria]

There is an issue when the plugin Index WP Users for Speed is active. That plugin uses the filter wp_dropdown_users_args (https://github.com/OllieJones/index-wp-users-for-speed/blob/51990c939e39d78489eb70732e0ef7a54b0c9e91/admin/user-handler.php#L267) so it overrides the args that are used to return zero authors and suppress the author selection (add_filter( 'quick_edit_dropdown_authors_args', static fn() => [ 'include' => [ 0 ] ] ); https://github.com/Automattic/Co-Authors-Plus/blob/30602dbd59c6cd73bd4aa3ff8a3e6eda0c1bccea/php/class-coauthors-plus.php#L551C4-L554C6), so we end up with both showing up and a messy quick/bulk edit box.

[jffaria]

I also opened an issue on their repository: OllieJones/index-wp-users-for-speed#22