Updating the stats tab in the preview pane to match design specs

[coder-karen]

Related to https://github.com/Automattic/automattic-for-agencies-dev/issues/109

Proposed Changes

• This PR updates the stats preview pane section in the sites dashboard to match design specs.
• Note - the designs do not include an external link icon, but the link goes to wp-admin, so for consistency with all other similar buttons I've added an external link icon.

Conversation around the stats section in Figma here, beyond what is included in the designs themselves: 1UpoqS1KkCtLXVX68TbMSM-fi-6144_260191#747621639

Testing Instructions

For the below testing steps, make sure to run yarn start-a8c-for-agencies locally and then visit http://agencies.localhost:3000/sites.

• Visit the stats tab when opening the preview pane for a site. It should match the design below, which should also match that which is discussed in the design specs linked above (with the addition of the external link icon).

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• https://wpcalypso.wordpress.com/devdocs/docs/testing/index.md 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-aUh-p2)?

[matticbot]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-102623

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-102623&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-102623&env=a8c-for-agencies

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

Sections (~23 bytes added 📈 [gzipped])

name                           parsed_size           gzip_size
a8c-for-agencies-sites              +215 B  (+0.0%)      +23 B  (+0.0%)
jetpack-cloud-agency-sites-v2       +170 B  (+0.0%)      +13 B  (+0.0%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[cleacos]

😍

[cleacos]

LGTM!