CI status icon mismatch on Merge Requests page and the MR itself

Summary

Success with warning status not determinable from Merge Request page (perhaps others).

Steps to reproduce

• Create a CI job with allow_failure set to True.
• Force that job to fail.
• Submit an MR with this CI change.
• Note Merge Request page of the project shows success for the pipeline.
  
• Note the MR itself shows more in depth status: passed with warnings.
  

Example Project

https://gitlab.com/benjamb/mr-status/merge_requests
https://gitlab.com/benjamb/mr-status/merge_requests/1

What is the current bug behavior?

MR pipeline status on Merge Request page shows green tick.

What is the expected correct behavior?

MR pipeline status on Merge Request page shows orange exclamation mark (or other identifier of success with allowed failure).

In terms of prioritization of types of pipeline (low to high priority)

Branch pipeline < merge request pipeline < post merge pipeline

With https://gitlab.com/gitlab-org/gitlab-ee/issues/7380 this might turn into

Branch pipeline < merge request pipeline detached < merge request pipeline (on merged result) < post merge pipeline

This bug happens on GitLab.com.

/label ~bug