Block comments: Add support for comments on published posts

[joemcgill]

Description

This sub-issue is part of #66377

The ability to add block level comments to published posts was removed in #66583. However, there are many use cases where a published post may still be updated after it is initially published, so additional comments should be able to be created once the post is published.

Step-by-step reproduction instructions

1. Enable the block level commenting experiment in wp-admin/admin.php?page=gutenberg-experiments
2. Create a new draft
3. Add block comments to the post
4. Publish the post
5. Notice that no new comments can be added to blocks on the post

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure