Dev: Allow a domain requestor to tell us if they're working with a person from CISA regions

[vickyszuchin]

Issue description

Knowing that a requestor is working with staff from CISA regions can be helpful. We should ask a question about it in the request form. Follow the designs laid out in this Figma page (more detailed AC below)

Acceptance criteria

• Refer to content google document as source of truth
• On the Anything else? page, change page title to "Additional details"
• Add These questions are required (*). under the page title
• Add a new question asking if the user is working with a CISA regional rep (Figma link) Follow the google doc for content and Figma for design and placement
• Move the Anything else question below the CISA regional rep question. This question is turning into a radio button instead of an optional open field. (Figma designs) Follow the google doc for content and Figma for design and placement
• In Django admin expose these fields according to Figma designs
• For behavior of the conditional fields, follow the logic used in the other employees page.
• For errors, follow the errors laid out here and here

Additional context

No response

Links to other issues

Related to: #1891 (design ticket)

[vickyszuchin]

"Block" tag added: depended on design ticket (#1891)

[vickyszuchin]

Moved out of sprint 41because of dependency on design ticket. Added "carryover" and added to sprint 42. cc: @abroddrick

[gabydisarli]

Can we make a small tweak this error message?

Instead of "your" email, can we say Enter the email of your representative in the required format, like name@example.com.