Allow WC Shipping to use larger migration state machine enums

[kallehauge]

Description

We'll start using the "state machine" in WC Shipping as well to make the overall structure a bit more consistent.

That means we cannot guarantee that WCS&T will know all states anymore, so this PR aims to disable our migration banner / feature announcement modal when the value is greater than COMPLETED.

I also sneaked in a few __().

Related issue(s)

• https://github.com/woocommerce/woocommerce-shipping/pull/696/

Steps to reproduce & screenshots/GIFs

1. Checkout trunk
2. Disable WC Shipping (if it's enabled)
3. Run wp option set wcshipping_migration_state 13 ("COMPLETE" is 12, so 13 or anything higher will be good for testing)
4. Go to /wp-admin/admin.php?page=wc-orders
5. Verify you see the migration banner
6. Go to any shippable order
7. Open the Create shipping label modal
8. Verify you see the Feature Announcement modal
9. Checkout this branch
10. Refresh the order page
11. Open the Create shipping label modal
12. Verify the Feature Announcement is no longer showing
13. Go to /wp-admin/admin.php?page=wc-orders
14. Verify the banner is no longer showing
15. Bonus!
    • Run wp option set wcshipping_migration_state 1 and verify the banner and feature announcement modal is showing since it's in a "not begun" state.
    • Run wp option set wcshipping_migration_state 12 and verify the banner and feature announcement modal is hidden since it's in a "COMPLETED" state.

Note: you might have issues seeing any of the migration banners/modals if you have the wcst-wcshipping-migration-dismissed cookie that temporarily hides everything.

Checklist

• unit tests

• changelog.txt entry added
• readme.txt entry added

[kloon]

Works as described, thanks for thinking pro-actively about the changes we make in WC Shipping and how it affects WCS&T.