Show both author and committer in last commit info box

What does this MR do and why?

Ensures the committer info is also displayed in the last commit component if it differs from the author.

Note: committer avatar and link to their profile will be done in a follow-up since this info is not available in the GraphQL endpoint yet.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Create a new project with a README.md file in GDK.
2. Clone the project and make a change to the README.md file.
3. Create a commit with a different author to committer for the change, eg git commit --author="Author Name <author@example.com>" -m "Commit message"
4. Push the change and go to the project root, eg http://gdk.test:3000/root/new-project
5. Select the README.md file to navigate to the blob viewer.
6. Both the Author and Committer should be displayed in the last commit component

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.

Related to #544803 (closed)