Site Migration: Indicate that you own the plan on the Migrate vs Import step

[gabrielcaires]

Closes #97740

Proposed Changes

• Refactor to make the copy decision more explicitly
• Update logic to show the Requires Business plan based on whether it is possible to install plugins instead of checking the existing plan name.

Screenhots

1. Free site
   

The site already has the business plan

E-commerce plan

Testing Instructions

Free site

• Go to /setup/hosted-site-migration
• Create a new site (free plan)
• Follow all steps until the Import or Migrate step
• Check if you can see the label (Screenshot 1)

business plan site

• Create a new site using a business plan
• Go to /setup/hosted-site-migration
• Select the site using the business plan
• Follow all steps until the Import or Migrate step
• Check if you can see the label (Screenshot 2)

ecommerce plan site

• Create a new site using a ecommerce plan
• Go to /setup/hosted-site-migration
• Select the site using the ecommerce plan
• Follow all steps until the Import or Migrate step
• Check if you can see the label (Screenshot 3)

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-129741

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-129741&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-129741&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 update/show-plan-is-included on your sandbox.

[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.

[andres-blanco]

why is this copy changed?