docindex runs should be reporting warning, not success when there are packages that fail validation

When trying to help onboard azureml-featurestore, the CSV was updated, the json was created and the python - docindex pipeline was green which leads one to believe that everything passed when, in fact, they didn't. I recognize that docs are "best effort" but if packages fail the [Update Docs Onboarding for main branch](https://dev.azure.com/azure-sdk/internal/_build/results?buildId=3269496&view=logs&j=dc056dfc-c0cf-5958-c8c4-8da4f91a3739&t=51aa7976-5924-5040-41de-f124a4debc20&l=546) step shouldn't be green, it should be orange. I believe we'd want to return `SucceededWithIssues`.

A secondary thing to do here would be to save up the errors and report them all at the end rather than having to mine 500+ lines of log looking for errors looking for interspersed warnings.