CR: Add email validations to ensure the users enter their email correctly right away

Can we please add some validations to ensure that citizens registering a STRR enter their email correctly the first time?

Ideas:
1. Make the users enter it twice and they have to match to pass validation
2. Check that it is a valid domain.

Start by locating the STRR registration flow and its existing email validation entry point. Determine whether the intended behavior is matching email fields, domain validation, or both; done should include agreed validation rules and coverage for the registration cases.

Written by the indexing model from the issue text.