Add ability to run `pull_request` action on a select branch

[schaubh]

• Review: By commit
• Merge strategy: Merge (no squash)

Description

To test that the CI integrated tests build and run properly we had to setup a draft PR that couldn't be deleted afterwards. The pull request action has been updated such that it can now be called on a select branch before even creating a PR.

Verification

Installed GitHub GL (https://cli.github.com) to test

gh workflow run pull-request.yml --ref feature/workflow_dispatch

This caused GitHub to run the pull request action script on the branch feature/workflow_displatch

Documentation

Added release notes

Future work

None