This tiny update addresses an issue that affected detection of the assigned blog page.

Detailed log

> View code changes.
> View closed GitHub issues.

For everyone

• Fixed: The blog-as-page can be detected correctly again.

For developers

• Added: Method tsf()->query()->utils()->has_blog_page() is now available.
• Removed: Method tsf()->query()->utils()->blog_page_exists() is gone without deprecation. The method only existed for a day and we found that has_blog_page was a better name.