Implement new certifier info flow (required email)

[michaelclement]

As the IVC team, we need to make sure that every user who fills out 10-10d is providing a valid email address so that we can contact them in the event of a silent failure.

Figma

Explanation Based on this ticket (and this), we are going to refine the Certifier Information flow of 10-10d to make it mandatory of all users. Then we're going to take the information entered there, and if the certifier is also "Applying for benefits for myself", we will populate the first applicant in the list with that information so they don't have to re-enter it.

Acceptance criteria

• Certifier/signer role screen is removed
• Certifier/signer info flow is required of all users
• New checkbox for "I'm applying for benefits for myself" is added to the end screen of certifier info section
• When certifier is applying for benefits for himself, certifier information (name, address, phone, email) are automatically duplicated to the first applicant slot in the list loop
• Certifier email field is required
• Form signature must always match the certifier name

[michaelclement]

Additional considerations:

• Cypress test data will need to be updated
• Unit tests will need to be updated
• Adding the certifier to the applicants array should not damage any existing SIP data
• We will need a migration (or at least to change the version number of the form) since it has already technically been deployed in the production environment.
• Make sure the certifier information section is NOT populated on the PDF if the certifier is an applicant.
• Make a separate BE PR to remove any references to certifierRole or certifier_role in vets-api since that property will be removed.