Do not start this work if the new headers are not on master

Scope

• Modify the Run screen design so we can surface a branch or PR link
• If the run is for a PR then it should read "Pull Request" instead of "Branch"

Notes
There is an API for retrieving the pull request and branch links here

Design Brief

Developers desire a link back to Github for or branch and pull requests contextually in Blue Ocean.

At a minimum it would be useful if a developer could click through to the web interface on Github for a branch or PR from the Run screen.