grab the correct username when confirming secondary email

What does this MR do?

When confirming a secondary email address and the user is not logged in, then a log message was trying to grab the username from the wrong object.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

To fix issue #39366 (closed)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #39366 (closed)