Remove the default branch name in the search result page tip

What does this MR do and why?

The default branch may not be accessible to the user. So, we'd prefer not to display in the search result page tip.

Screenshots or screen recordings

Before the change

After the change

These are strongly recommended to assist reviewers and reduce the time to merge your change.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #347501 (closed)