Fix list grid view alignment

[CipherZ3r0]

Closes #13352

FIX : This fixes the alignment of the Preview action in the list/grid view when a book does not have a preview available.

Technical

• Updated openlibrary/macros/BookPreview.html to handle books without an ocaid.
• Previously, the Preview action was only rendered when an ocaid was present, which caused the CTA area to be missing and resulted in inconsistent alignment.
• Added a fallback No Preview state when no ocaid is available.
• The unavailable state is rendered as a non-clickable <span> rather than a link.

Testing

• Verified the updated UI locally using the Docker development environment.
• Ran the Python test suite:
  • 5738 passed
  • 18 skipped
  • 5 deselected
  • 1 xfailed
• One unrelated existing failure remains in TestHomeTemplates.test_home_template due to the missing QueryCarousel macro in the test environment.

Screenshot

Stakeholders

@RayBB