Fixes diff stats not being visible with performance bar

What does this MR do?

Fixes diff stats not being visible in the diff file tree when the performance bar is enabled.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides