Fix invite by email address duplication

What does this MR do?

Fix invite by email address duplication. Currently the email address is displayed where the user's username is normally rendered. This is not necessary for invites by email so we should just hide the second username/email reference

Before:

After:

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

There are no tests for the new functionality.

Adds a little bit more text to specify that the invite is by email

Why was this MR needed?

Please see #36937 (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 #36937 (closed)