Feature request: allow access to pull request conflict status via API

Related to BCLOUD-6645, but for the API.

I'm using your API (v2) to build a status board for all of the PRs that our team has open across a handful of repositories.

This works nicely, and I can show a good amount of information directly on the status board. However, for PRs with source conflicts, I'd like to show that directly on the status board so that the author can see it needs attention, and reviewers can know to wait until later.

(I'm using Mercurial, in case that makes a difference.)