#7727756 Show domain information to user if migrate the site using plugin

Proposed Changes

• If a user comes from the migration plugin and starts from the siteCreationStep, we’ll offer them to add domain at the end of the migration progress.

Testing Instructions

• Launch a JN site with migration plugin and click Set up Jetpack to connect the site to your target site user account, or use any self-hosted site you’ve already connected to your target user account.
• Once it’s done, navigate to http://calypso.localhost:3000/setup/import-focused/siteCreationStep?from=${TARGET_SITE_SLUG}. The TARGET_SITE_SLUG here should be the site you want to migrate. For example, a testing Jurassic Ninja site.
• Going through and finishing the migration process.
• Once it’s finished, see if you get a screenshot with your domain information.
  
• Click Update domain name button and see if it brings you to the domains/add/${SITE_SLUG} page.

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the “[Status] String Freeze” label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the “[Status] Needs Privacy Updates” label if this pull request changes what data or activity we track or use (p4TIVU-ajp-p2)?

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