Fix bug and error message for vat_api testing

Currently, we're seeing 500 errors from several pipelines when attempting to retrieve findings from the vat findings api.

Example: https://repo1.dso.mil/dsop/redhat/ubi/ubi8/-/jobs/3004328

We'll need to look into why this is happening, and resolve the issue. We'll also want to update the error message in pipeline_wl_compare for this block of code (at the end of the pipeline_wl_compare() function)

else:
    logging.warning(f"Unknown response from VAT {r.status_code}")
    logging.warning(r.text)
    logging.error("Failing the pipeline, please contact the administrators")
    global api_exit_code
    api_exit_code = 3

so that it is less confusing. This else statement doesn't fail the pipeline, but it does soft fail the stage. We'll want to change the error message to prevent confusion when the pipeline hard/soft fails for a different reason.