A4A: Remove a4a-unified-onboarding-tour feature flag

[jkguidaven]

Context: pfSQfS-1sJ-p2

Proposed Changes

This pull request removes the "a4a-unified-onboarding-tour" feature flag and all related conditional logic, fully enabling the unified onboarding tour and cleaning up legacy onboarding code and UI. It also removes onboarding and quick links components that are no longer needed, simplifying the codebase and user interface.

Key changes include:

Feature flag and conditional logic removal:

• Removed the a4a-unified-onboarding-tour feature flag from all configuration files, making the unified onboarding tour always enabled. [1] [2] [3] [4]
• Deleted all code that checked isEnabled('a4a-unified-onboarding-tour') and updated redirects and UI logic to assume the unified onboarding tour is always active. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

Component and UI cleanup:

• Removed the legacy onboarding intro cards by deleting OverviewBodyIntroCards and its usage, along with its styles. [1] [2] [3]
• Removed the "Quick Links" sidebar component and its styles, as it was only shown in the legacy onboarding flow. [1] [2] [3] [4]
• Deleted the AgencyTierFeatureAnnouncement modal and its conditional display logic, as it is no longer needed with the unified onboarding experience. [1] [2] [3]

Why are these changes being made?

Ensures our codebase are maintainable by removing irrelevant codes.

Testing Instructions

• Use the A4A live link and navigate to /overview page.
• Confirm there is no regression.

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 tested accessibility for your changes? Ensure the feature remains usable with various user agents (e.g., browsers), interfaces (e.g., keyboard navigation), and assistive technologies (e.g., screen readers) (PCYsg-S3g-p2).
• 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-172288

Jetpack Cloud Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-172288&env=jetpack

Automattic for Agencies Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-172288&env=a8c-for-agencies

Dashboard Live (dotcom) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-172288&env=dashboard

Dashboard Live (CIAB) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-172288&env=dashboard-ciab

[matticbot]

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

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

• blaze-dashboard
• notifications
• odyssey-stats
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug remove/a4a/unified-onboarding-tour-feature-flag on your sandbox.