NewCommand creates a new Cobra command and a new Runner to unregister a configured cloud provider credential from the
Radius installation, and adds flags for output and workspace.
Run attempts to delete a cloud provider credential for a given Radius installation, and logs a message
depending on whether the credential was found and deleted or not.
Validate validates the command line arguments, workspace and output format, and checks if the cloud provider
name is valid, returning an error if any of these checks fail.