#7770039 Add suggested domain to upsell

Proposed Changes

• This PR adds a suggested domain to the domain upsell on My Home.
• We load the first paid suggested domain.
• Suggesting a domain takes some time so we load a spinner while we wait.

Testing Instructions

• Apply this PR locally
• Apply this diff to your wpcom Sandbox D99116-code
• Sandbox your API
• View the new “domain upsell” feature on My Home. It should show on any My Home page that’s in the site-setup state. AKA it has the checklist of things to do in the top right.
• There should be a spinner while the suggested domain loads.
• The spinner changes to “Available” when the suggested domain is loaded.
• Most likely the suggested domain will be the site-sub-domain.blog. But it could be something different if that domain is already taken.
• Because we use useLocale Test this in different languages to be sure it works properly.

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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