Theme showcase: Update the layout on the Global Site View

[BogdanUngureanu]

Related to #94950

Proposed Changes

• Update the layout of the Theme showcase (header and theme content)

Why are these changes being made?

• This PR makes the themes layout more consistent with the rest of the sections (Sites and P2)

Testing Instructions

• Use the calypso live link
• Go to /sites and then /themes global pages
• Notice that the "Themes" and the "Design your own" elements are aligned with the rest of the global pages (Sites is leading)
• Make sure that no regressions are affecting /themes/site-name and the logged out showcase

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-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-121838

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-121838&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-121838&env=a8c-for-agencies

[BogdanUngureanu]

@lucasmendes-design can you have a look at these changes (with the live link)?

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug update/global-themes-layout on your sandbox.

[matticbot]

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

Sections (~30 bytes added 📈 [gzipped])

name    parsed_size           gzip_size
themes       +199 B  (+0.0%)      +30 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.

[xavier-lc]

Shouldn't the Themes title be aligned with the content?

[BogdanUngureanu]

@xavier-lc not sure. The Sites looks aligned but it's not actually aligned (the most obvious one is on the right side of the page where the scrollbar is not aligned with the action button)

Lucas, any thoughts? :)

[mmtr]

The Sites looks aligned but it's not actually aligned (the most obvious one is on the right side of the page where the scrollbar is not aligned with the action button)

We don't have an equivalent button for Themes on the right side, so I don't think that's relevant.

But the page title is definitely aligned differently. In both pages should be aligned with the search bar: