Moving server builds to Buildjet to confirm if it's faster and more reliable
Also, cleaning up some CI workflows to remove references to release-frozen branch.
* Release frozen related changes
* Switched image used to PR head instead of target
* Update .github/workflows/client-test.yml
Co-authored-by: Arpit Mohan <mohanarpit@users.noreply.github.com>
* PRs into release should use release server code