[Testing] Re-configure Chromatic CI workflow

[RasmusKjeldgaard]

• [x] Run chromatic on Github action push event to avoid losing baselines: https://www.chromatic.com/docs/github-actions/#recommended-configuration-for-build-events
  • Seems like this is unneccessary, I have enabled the Chromatic Github app instead, which should carry over the baselines: https://www.chromatic.com/docs/github-actions/#github-squashrebase-merge-and-the-main-branch
• [x] How do we avoid running snapshot tests for each and every push to a PR?
  • Only run before merge of every PR? A label on PR?
• [ ] Configure Github branch protection rules to require status checks to pass before merging - both chromatic and UI Tests
• [x] Enable UI Review powered by stories