Getting commits or pr mentioned in issue

Description

Given a link to an issue, I am trying to retrieve commits and/or pull requests that are mentioned in any of the comments of the issue.

Commit:

Issue: ucloudvain/openjpeg#1126
Commit @619e1b0

The commit is mentioned in one of the comments.

Pull Request:

Issue: ARMmbed/mbed-os#11803
PR @12146

The PR is mentioned in one of the comments.

What I tried

I tried exploring all the different IssueTimelineItems to get to this information but without any success. Is it possible to retrieve this information using GraphQL API v4?