Az storage azcopy blob download prints access key

-### Related command
az storage azcopy blob download

### Extension name (the extension in question)
az storage azcopy

### Description of issue
Running ```az storage azcopy blob download --container --source --destination ``` outputs an object called Namespace as shown in line 237 at https://github.com/Azure/azure-cli-extensions/blob/main/src/storage-preview/azext_storage_preview/_validators.py. This Namespace object prints out the values of sensitive secrets such as storage account access keys/ connection string.

Running this in a job will expose the secret to any individual that has access to the job. Can we please redact these secrets from being printed in output?