New job doesn't report status to GitHub/VCS until it's actually running on K8S

[artem-zinnatullin]

As discussed with @DrJosh9000 there is an issue right now where neither Controller nor Buildkite backend report job status check back to VSC system like GitHub until job is actually running on K8S which can take very long time depending on the load on the cluster.

This is normally solved by configuring required check on GitHub, however there are cases like "New build" in Buildkite UI or API call triggered jobs which due to their nature cannot be added as required checks on GitHub thus they will not show up and can confuse PR author thinking that everything is green and PR will get merged even though there is a Pending Buildkite job.

I think Buildkite backend can send the status check since it knows Job is "Waiting for Agent", hopefully no buildkite/agent-stack-k8s changes are necessary for this.