Approval rules code owners

MR	Changes
!46738 (merged)	Part 1: Display approval rules
this MR	Part 2: Display "Code Owner"

What does this MR do?

If the approval rules is of code_owner, it will display the text 'Code Owner' instead of what is provided in the rule_name.

This was raised in this MR > !46738 (comment 460295496)

Current	This MR

Testing Case

Here's the docs to setup [Code Owners](http://localhost:3000/help/user/project/code_owners`. This is what I'm using:

* @root

1. Select a merge request that has some code changes
2. In the sidebar reviewers dropdown, you will see Code Owner

3. Click on "Edit", the reviewer dropdown will also have the same text

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
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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