fix(secrets): Write secrets warning to stderr instead of stdout

cmd/save.go

@@ -155,12 +155,17 @@ func (o *SaveOptions) Run() (err error) {
  }
 
  if o.Secrets != nil {
- if !confirm(o.Out, o.In, `
+ // Stop the spinner so the user can see the prompt, and the answer they type will
+ // not be erased. Output the message to error stream in case stdout is captured.
+ o.StopSpinner()
+ if !confirm(o.ErrOut, o.In, `
 Warning: You are providing secrets to a dataset transformation.
 Never provide secrets to a transformation you do not trust.
 continue?`, true) {
  return
  }
+ // Restart the spinner.
+ o.StartSpinner()
  if p.Secrets, err = parseSecrets(o.Secrets...); err != nil {
  return err
  }