Check that errors are empty in CI config spec

What does this MR do and why?

This checks that there are no pipeline errors when creating a pipeline in the CI configuration validation specs, so it's easier to investigate if they fail due to e.g. permission errors like in !175588 (closed).

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.