x/build/cmd/relui: merge 'Start Google Docker build' + 'Await Google Docker build' into one retryable task

[dmitshur]

The Google Docker build task is currently made of two tasks: one to start a Cloud Build invocation, and another to await its result. This has a flaw in that if the Cloud Build invocation happens to fail (with a retryable failure, such as a temporary internet connectivity error), it's not possible to retry it via relui UI. It will keep awaiting the original Cloud Build invocation, even if it failed.

This is the tracking issue to improve that, so it will be possible to resolve retryable failures in relui (either via the automatic 3 retries, or with a manual retry).

CC @dr2chase, @golang/release.

[gabyhelp]

Similar Issues

• x/build/cmd/relui: better retry support #54304

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}