Sites Dashboard: Remove the max-width for the banner

[okmttdhr]

Related to https://github.com/Automattic/dotcom-forge/issues/9915

Proposed Changes

This PR is a follow-up for #96713 (comment).

Why are these changes being made?

pbxlJb-6DF-p2

Testing Instructions

• Comment out this line to show the banner on your local Calypso. (I wasn't sure how to show the banner.)
• Go to /sites
• Observe the banner is aligned with the "Sites" and DataView.
  • in the large view > 1440px
  • in the mobile view (especially > 430px)

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 UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• 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-125671

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-125671&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-125671&env=a8c-for-agencies

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[okmttdhr]

@oandregal
This 430px is derived from Core. Would it make sense to update it to $break-mobile: 480px;? If so, I’m happy to create a PR.

[oandregal]

What I know is that it was introduced as part of this PR (and then the code was moved around, so it was a bit difficult to track). I'll defer this one to designers. Can you raise this to them?

[okmttdhr]

Thanks for taking a look at it! Left a comment for now: WordPress/gutenberg#61333 (comment)

[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 fix/max-width-banner on your sandbox.

[madhusudhand]

Verified the banner in different viewports. It is set to the right width and matches sites header and dataview actions.