Fix non-escaped % character in Repository Analytics

What does this MR do and why?

Fixes a non-escaped % character in the Repository Analytics page

References

• y-axis of the Code coverage statistics graph ha... (#457543 - closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.