How do I add a contact from iMessage in iOS 11?

When a new person messages me, I used to be able to use the message to add their phone number to my contacts. But since upgrading to iOS 11, this doesn't work anymore.

When I click on the "i" next to the phone number, I see a screen with options to send or share my location, hide alerts, facetime, call, etc. But no option to add the person to my contacts.

A previous tip for iOS 10 said I had to click on the phone number to add the person to my contacts, but when I do that, I get a blank screen with an "Edit" link. If I click on the Edit link, I get the option to add every sort of contact info except the person's name!

This is very frustrating. To add my new friend's contact info in iOS 11, I have to follow these steps:

1. Copy down phone number from iMessage onto a piece of paper.
2. Open the Phone app and select the Contacts icon.
3. Click the + button to add a new contact.
4. Type in my friend's name and phone number.

Please tell me there's a better way to do this!