only raise error in config-is-valid if format is bad
Should remove the remaining PreviousStepFormatError: https://github.com/huggingface/dataset-viewer/issues/2433#issuecomment-2179014134
only raise error in config-is-valid if format is bad: Should remove the remaining PreviousStepFormatError: https://github.com/huggingface/dataset-viewer/issues/2433#issuecomment-2179014134