What?

Closes #71245

This PR restores the ability to add block-level comments on published posts. Previously, the functionality was removed in #66583, but this update ensures that users can continue to add comments even after a post has been published.

Why?

There are many use cases where published posts still receive updates or collaborative changes. Without this fix, users cannot add block-level comments once a post is published, which limits collaboration and feedback opportunities.
This PR makes block commenting consistent across draft and published states.

Testing Instructions

1. Enable the block-level commenting experiment via
   wp-admin/admin.php?page=gutenberg-experiments.
2. Create a new draft.
3. Add block comments to one or more blocks.
4. Publish the post.
5. Verify that new comments can still be added to blocks on the published post.

Testing Instructions for Keyboard

1. Navigate to a published post using only the keyboard.
2. Focus on a block that already has comments.
3. Confirm that it is possible to add a new block comment via keyboard navigation (no reliance on mouse).

Screenshots or screencast