Fix missing MR widget status icons

What does this MR do?

Fix missing MR widget status icons (update to actually use SVG sprite map)

Before	After

Are there points in the code the reviewer needs to double check?

This regressed in https://gitlab.com/gitlab-org/gitlab-ce/commit/d01d509bd8612f9879fa762de8ea3763bcff81cf via https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/14567 where we refactored ci_icon.vue to grab the SVG from the sprite instead of a map in ci_status_icons.js

Why was this MR needed?

Status icons were missing in the Merge Request widget.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by Frontend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

Closes #40283 (closed)