Add verification deadline messaging to verify email form

What does this MR do and why?

Add verification deadline messaging to verify email form.

References

• #587957

Screenshots or screen recordings

Before	After

How to set up and validate locally

You need a user that has a high risk profile in order to test this. Here's the most reasonable way of achieving this:

1. Check out this branch

2. Log into the GDK as an admin

3. impersonate a user that you DO NOT NEED to regularly use, as this process may cause problems for that user

4. Open the rails console (bin/rails c)

5. Run this in the rails console:

   user = User.find_by(username: 'USERNAME_GOES_HERE')
   user.assume_high_risk!(reason: 'Testing identity verification')
   user.update!(confirmed_at: nil)

6. In the GDK, visit https://gdk.test:3000/users/identity_verification

7. You should now be able to see the verification form, starting on email verification

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #587957