Display Contributor and Author badges on notes

What does this MR do?

Closes #16534 (closed)

• A Contributor badge appears in notes of users who have created MR merged into default branch.
• Also, notes of an issue, MR, commit, snippet author have an Author badge. ¹

---

• A badge is added to the issue and MR header. ¹

ToolTip

Contributor	Author	Member

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
• 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

1. It does not appear on mobile screen. ²

app/models/merge_request.rb

@@ -1558,7 +1558,7 @@ def update_project_counter_caches
   def first_contribution?
     return false if project.team.max_member_access(author_id) > Gitlab::Access::GUEST
 
-    project.merge_requests.merged.where(author_id: author_id).empty?
+    !project.merge_requests.merged.exists?(author_id: author_id)
   end
 
   # TODO: remove once production database rename completes