"Notes" mailbox visible in Account Info but missing from mailbox list

I have a mailbox called "Notes" in my iCloud email account that I cannot access in the typical way in Apple Mail on macOS. It is missing from the list of mailboxes in the Mail sidebar. I can, however, see that the mailbox (IMAP folder) exists by control-clicking my iCloud Inbox and selecting Account Info. You can see Apple's instructions for how to do this here. Also, there is a message in this mailbox as well. I would like to either access it or delete the mailbox so it is no longer visible in Account Info to clean things up.

Here is a screenshot of what I see on the Account Info window:

Can someone please give me instructions or advise on how to access this mailbox folder or delete it? Thank you!