Blaze Pro 2FA login screen: fix layout and styling issues

[andrewserong]

Follow up to: #102811 and #103445, thanks to @adamwoodnz for catching this!

Proposed Changes

• Ensure Blaze Pro 2FA screens don't get the is-white-login treatment (they skip it in the usual login screen, but the 2FA screen was still getting the top masterbar + common styling)
• In logged-out, factor in that the oauth2 client isn't always in the query string. On the 2FA screen, it's in state, so we need to include that in the check for isWhiteLogin
• Ensure that the styling that unsets the max width on the login form only applies when the expected login form is present. This will allow the 2FA version of the screen for Blaze Pro to not be full width, and render as expected.

Why are these changes being made?

• As raised in Update content area of login screens to use StepContainerV2 #102811 (comment) the login 2FA screen for Blaze Pro is currently not displaying correctly

Testing Instructions

• In an incognito browser and with a WordPress.com account that has 2FA enabled, go to https://blazepro.com/ and go to log in
• Once you land on the log in screen, copy the query string for the route and paste it into a local URL with this branch checked out, and paste it into your browser bar after this url: http://calypso.localhost:3000/log-in/
• That should take you to the Blaze Pro login screen
• Log in with your username and password, and check that the 2FA screen displays correctly
• Smoke test other variations of the login screens to make sure nothing is broken as a result of this PR

Screenshots

Before	After

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)?

[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 try/fix-blaze-pro-2fa-screen on your sandbox.

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-145262

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-145262&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-145262&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.

[adamwoodnz]

Thanks for picking this up!

Works for me, just one question inline.

[andrewserong]

That one-liner's testing well for me, too. Thanks for taking a look @adamwoodnz! 🙇

[adamwoodnz]

LGTM!