Add user popup to CI pipeline header

What does this MR do and why?

This MR adds the user popup to the CI pipeline header to make it consistent with other headers (like issue or merge request headers) that already show the user popup when hovering over the user’s name and avatar.

Related to #322547 (closed)

Screenshots

Before	After

How to set up and validate locally

1. Go to a project that has CI set up (or create one)
2. In the sidebar, click on CI/CD > Pipelines
3. Click on one of the pipelines
   • if there are none: start a pipeline
4. See the header of the pipeline

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.