Avoid counting post editor admin inline comments alongside user comments

[JeffPaul]

The new Inline Comments feature currently causes admin/editor inline comments to be included in the overall user comment count on the All Posts screen. This inflates the visible count and mixes editorial feedback with actual user-submitted comments, which can confuse site admins and editors.

This was first identified in Gutenberg (​issue#71621) and a PR was opened in wordpress-develop to address it (​PR#9869).

As @adamsilverstein ​noted, this should be properly tracked in Core (and thus a Trac ticket here).

Steps to Reproduce:

1. Enable Inline Comments.
2. Add one or more inline comments in the block editor.
3. Visit WP Admin → Posts → All Posts.
4. Observe that the comment count for the post includes both user-submitted comments and editor/admin inline comments.

Expected Behavior:

• The comment count on the All Posts screen should reflect user comments only.
• Inline editorial/admin comments should not be included in this count.

Actual Behavior:
Inline editorial/admin comments are included in the count, leading to inflated and misleading numbers.

Proposed Fix:
Adjust the query/count logic to exclude inline editorial/admin comments from the standard comment count displayed in the admin UI.

This PR modifies the get_pending_comments_num() function to exclude editorial comments from the pending count and makes the function more extensible.

Changes Made:

Fixed the query by excluding block_comment type.

Added extensibility: Introduced the pre_get_pending_comments_num filter hook. This allows developers to modify the query arguments used for counting, making it future-proof for custom comment types or additional filtering needs.

Trac ticket: https://core.trac.wordpress.org/ticket/64012

[wildworks]

Duplicate of #64096.