#7834684 Jetpack Pro Dashboard: implement site expanded content & add insights card

Related to 1203940061556608-as-1203942568420853 & 1203940061556608-as-1204038366237501

Proposed Changes

This PR implements the site expanded content and adds a 7 days insights stats card.

Testing Instructions

Prerequisites

Since these changes are made specifically for agencies, you must set yourself(partner) as an agency – 2c49b-pb. Make sure to switch it back to the previous type.

NOTE: These changes are behind a feature flag and will not be effective in production immediately after merging.

Instructions

1. Run add/site-expanded-content and yarn start-jetpack-cloud
2. Open http://jetpack.cloud.localhost:3000/, and you’ll be redirected to the /dashboard.
3. Click on the expand icon, and verify that you can the 7 days insights stats card as shown below. Clicking on “See all stats` does nothing. We will update the links in a different PR

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)?