Remove CrowdsignalOauthMasterbar and usage in logged-out

[chriskmnds]

Fixes https://linear.app/a8c/issue/DOTCOM-13395/crowdsignal

Proposed Changes

This follows up from #103830 to completely remove the custom CrowdsignalOauthMasterbar.

We are doing this separately to unblock the Login migration and test/confirm that no other usages exist outside of the Login screen. It is part of the logged-out layout for Crowdsignal, presumably more general than Login.

Why are these changes being made?

Part of https://linear.app/a8c/issue/DOTCOM-13395/crowdsignal

Testing Instructions

• Build passing. No other references exist for this component.

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-146645

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-146645&env=jetpack

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https://calypso.live?image=registry.a8c.com/calypso/app:build-146645&env=a8c-for-agencies

[matticbot]

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

App Entrypoints (~435 bytes removed 📉 [gzipped])

name                   parsed_size           gzip_size
entry-reauth-required      -1581 B  (-0.1%)     -435 B  (-0.1%)
entry-main                 -1581 B  (-0.1%)     -435 B  (-0.1%)
entry-login                -1581 B  (-0.1%)     -435 B  (-0.1%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

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

• help-center
• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug update/connect-refresh-login-crowdsignal-masterbar-removal on your sandbox.