Allow admins to update user information - email

[trillium]

Overview

Unless we pester Josh to edit all the emails with capitals, we're gonna need to do it ourselves. Right now we don't have a tool to allow admins to update a user's email address. Let's build it!

Action Items

• [x] #1496
• [ ] Create a UpdateUserEmail component that will be added to the EditUsers page
• [ ] Create a form validation that checks if the user's email already exists (except the current email on their account)