Mail doesn't provide option to delete a Mailbox I accidentally created
I'm running High Sierra. I did something in Mail, and seemed to notice peripherally that the list of mailboxes on my left seemed to expand. Then I thought I noticed a new folder I've never used (it was empty) called "VIPs". With "VIPs" selected, went to menu bar and selected "Mailbox". The option to "Delete Mailbox" is grayed out. I tied using a suggestion to use "Go to Folder" under the "Go" menu in Finder to go to "~/Library/Mail/V4" and delete the Mailbox there, but Finder says, "The folder can't be found". Am I stuck with "VIPs" folder in Mail?
iMac 27″, macOS 10.13