Sites Dataview: Update margin alignment

[DustyReagan]

Related to #94200

Proposed Changes

• This PR updates the margin of the header and data view on /sites. This is primarily achieved by removing custom styles and relying on the data view's built-in styling, though a little custom styling is still required.
• Of note is that this PR aligns the "Actions" column to the right to clarify the righthand design "lines." I removed this from this PR, so no special modifications are made to the "Actions" column.

Before:

Screen.Recording.2024-09-19.at.11.02.07.AM.mp4

After:

Screen.Recording.2024-09-19.at.11.00.43.AM.mp4

Why are these changes being made?

• Improved design for improved customer experience.

Testing Instructions

• Use Calypso Live
• Go to /sites and test multiple widths and mobile views.
• Open and close individual site panels to check for regressions
• Check other sections like /plugins and /themes to ensure no style bleedover.

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-119990

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-119990&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-119990&env=a8c-for-agencies

[matticbot]

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

Sections (~8 bytes removed 📉 [gzipped])

name                parsed_size           gzip_size
staging-site              -20 B  (-0.0%)       -8 B  (-0.0%)
sites-dashboard           -20 B  (-0.0%)       -8 B  (-0.0%)
site-performance          -20 B  (-0.0%)       -8 B  (-0.0%)
site-monitoring           -20 B  (-0.0%)       -8 B  (-0.0%)
site-logs                 -20 B  (-0.0%)       -8 B  (-0.0%)
hosting-features          -20 B  (-0.0%)       -8 B  (-0.0%)
hosting                   -20 B  (-0.0%)       -8 B  (-0.0%)
github-deployments        -20 B  (-0.0%)       -8 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.

[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/sites-dataview-alignment on your sandbox.

[allilevine]

Awesome to see all of those style hacks removed, and it's working well for me. I'm just not sure about aligning the "Actions" column to the right, and staying aligned with core.

[youknowriad]

Nice cleanup 👍