Style empty sites component to match the design

[wojtekn]

Proposed Changes

Style empty sites component to match the design:

• added new illustration for empty sites page
• adjusted font sizes and spacing

Testing Instructions

Empty sites

1. Modify SitesDashboard component and set allSites to the empty array: const allSites = [];
2. Load /sites-dashboard and confirm that the page matches the design

Empty status

1. Modify useSitesTableFiltering and set a subset of sites to empty e.g. filteredByStatus['public'] = [];
2. Load /sites-dashboard?status=public and confirm that the page matches the design

Repeat steps for 'private' and 'coming-soon' statuses.

Pre-merge Checklist

• [ ] ~~Have you written new tests for your changes?~~
• [x] Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• [x] 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)?

Related to https://github.com/Automattic/wp-calypso/issues/66211

[github-actions[bot]]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-39812

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-39812&env=jetpack

[matticbot]

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

Sections (~103 bytes added 📈 [gzipped])

name             parsed_size           gzip_size
sites-dashboard       +260 B  (+0.2%)     +103 B  (+0.2%)

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.

[p-jackson]

Screenshots for reference:

[p-jackson]

Changes look good to me. @SaxonF said that he had intentionally given the other empty states a different style, so I'd leave that up to him. I like the consistency, but on the other hand, the public/private/coming-soon pages don't have such a strong call to action with them, so they are different. Perhaps we don't want to water down our standard empty state styling by using it for cases that don't have such strong calls to action.

[SaxonF]

I do see them as different, particularly now that we are treating status more like a filter. They are more like an empty search as opposed to an empty state that leads to a clear next task (e.g. create new site).

[SaxonF]

In saying that, the screenshots look good and I don't feel too strongly about this. Let's leave as is.