Resolve "Top nav search bar produces console error when unauthenticated"

What does this MR do?

Eliminates error caused when using top nav search bar while unauthenticated.

Why was this MR needed?

#49861 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Conforms to the code review guidelines
  • Has been reviewed by a Frontend maintainer
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #49861 (closed)