Resolve "Code Review Analytics: Add approvers to table"

What does this MR do?

In !22871 (merged) we added the Code Review Analytics MVC. Due to high velocity development, the table was implemented without the Approvers column.

This MR adds the Approvers column to the table. It will show max. 2 approver avatars and a badge next to it with the number of remaining approvers.

In addition, tooltips for the author and the approvers are also added.

Screenshots

Before	After

Tooltips

approvers_tooltips_revised

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #197883 (closed)