Add non_archived param to group merge requests API endpoint

What does this MR do?

#28352 (closed)

Similarly to Issues, when fetching group merge requests using the API endpoint GET /groups/:id/merge_requests, it shouldn't return results from archived projects by default. This could be done by setting the param non_archived to false:

GET /group/:id/merge_requests?non_archived=false

See #28352 (comment 271828905)

Screenshots

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

Closes #28352 (closed)