Added committer user to merge request commit list

What does this MR do and why?

The committer can be different when users suggest a change and a different user applies the suggestion. This just makes that data visible within each commit row on the merge requests commit list.

Closes #329227 (closed)

Screenshots or screen recordings

How to set up and validate locally

• Create a code suggestion on a diff
• Apply the suggestion with a different user
• Navigate to the commits tab on the merge request

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.