Fixes a runtime error on empty repo

What does this MR do and why?

Quickfix for empty repo star button handler.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Create a repo, and don't bootstrap it with any files
2. Open that repo, check for errors in the browser console
3. Push some files to this repo, or open an existing repo with files
4. Check the star button working

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.