Display email verification message in response to forbidden errors coming from the backend

When a new user without a verified email address tries to take a write action, the back end will throw an error. The front end should catch the error and re-display the error message.

Estimating this card with a large budget because there's going to be a lot of corner cases that crop up

• Display the email verification banner whenever the user tries to do a write action
• Catch the forbidden error from the backend
• unit tests
• e2e tests