Migration: Add credentials step

[gabrielcaires]

Proposed Changes

• Add the new CREDENTIAL STEP on the migration flow

Testing Instructions

Scenario 1: No FROM information

• Go to /setup/migration
• Select WordPress
• Make the upgrade and payment
• On the Need a hand? select Do it for me
• Check if you can see the credential screen instead
• Fill the credentials
• Click on continue.
• Check if you reach the end of the flow
• Check if a ticket was created.

Scenario 2: From is available

• Go to /setup/migration?from=[WORDPRESS_SITE]
• Make the upgrade and payment
• On the Need a hand? select Do it for me
• Check if you can see the credential screen instead
• Check if the Site Address field was already populated.

Scenario 3: Skip
Follow all steps described in Scenario 1 until the step Tell us about your site.

• Click on Skip, I need help providing access
• Check if you can see the /migrateMessage step.

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-117872

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-117872&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-117872&env=a8c-for-agencies

[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 add/credentials-step on your sandbox.

[gabrielcaires]

#94025

[matticbot]

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

Sections (~113 bytes added 📈 [gzipped])

name            parsed_size           gzip_size
migration-flow       +324 B  (+0.5%)     +113 B  (+0.9%)

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.

[andres-blanco]

I ran through the flow with and without URL and it behaves as expected