Update work_search.html

[longbui23]

Closes #10049

This PR does these things:

• Add an option to "add a new book" when no results are found on the book search page
• Ensure the layout aligns with the page and stakeholder expectations

Technical

• Insert an HTML anchor (<a>) element with the following attributes:
  • href="/books/add": Links to the "/books/add" route
  • class="btn btn-primary": Applies Bootstrap button styling
  • Content: Displays localized text for "Add a new book" using $_() function
  • Enclosed in a closing </div> tag, suggesting it's part of a container

Testing

• Use the automatic testing.
• Confirm that the new button is added for adding a new book if no results are found on the book search page
• Cross-check for any visual inconsistencies on related pages and expectations of the stakeholder.

Screenshot

Stakeholders

@RayBB

[longbui23]

Co-author: @QuangPhung15