Creates an icon only for the discussions and puts back the old SVG for CI status

What does this MR do?

Fixes broken ci status icon by creating 2 SVGs, one for the discussions the other for CI status (introduced in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13821/diffs#929e82e72cc726770744570769797f5eb0f01990)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [ ] Documentation created/updated
• [ ] API support added
• [ ] Tests added for this feature/bug
• Review
  • [ ] Has been reviewed by UX
  • Has been reviewed by Frontend
  • [ ] Has been reviewed by Backend
  • [ ] Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #37406 (closed)