Site settings: allow site to be deleted if only purchases are non-refundable premium themes

[bluefuton]

Changes proposed in this Pull Request

Currently, it is not possible to delete a site with any active purchases. We direct the user to their Purchases to cancel everything first.

Premium themes are a special case, in that it is not possible to cancel them after they're outside the refund period. Users with a premium theme therefore are unable to delete their site.

This PR allows users to delete a site if the only purchases attached to it are non-refundable premium themes.

Testing instructions

Visit http://calypso.localhost:3000/settings/general and test with sites that:

• Only have premium themes that are not refundable. Verify that you can now proceed with site deletion.

• Do not have any premium themes or purchases. You should still be able to proceed with site deletion.

• Have purchases besides premium themes. Verify that you are shown the warning popover, and that it is not possible to delete the site.

Fixes #17012.

[matticbot]

Test live: https://calypso.live/?branch=fix/delete-site-premium-themes

[bluefuton]

Related PR dealing with the same scenario for account closure: #27411.

[ghost]

That's a great PR description, thank you so much for your effort!

Generated by 🚫 dangerJS

[KokkieH]

Tested using these steps:

Test 1

1. Purchased a premium theme on a new site on a test account using PayPal so there's a refundable transaction
2. Ran the branch locally and visited Purchases - Theme shows cancel and refund option
3. Went to My Site ->Settings and click on Delete your site permanently

Saw an overlay prompting me to cancel my upgrades prior to deleting the site. After cancelling and refunding the theme I'm able to delete the site.

Test 2

1. Purchased a premium theme using credits so the theme won't be refundable
2. With this branch running, visited Purchases and confirmed theme does not show as refundable
3. Went to My Site ->Settings and click on Delete your site permanently

I was able to successfully confirm and finish deleting the site without having to remove the theme.

Test 3

1. Purchased the Personal Plan as well as a Premium Theme using credits.
2. With this branch running, went to My Site ->Settings and attempt to delete the site.
3. See overlay that I need to cancel my upgrades first.
4. Visit Purchases and cancel the plan - theme is non-refundable and cannot be cancelled
5. Go back to My Site ->Settings and attempt to delete the site.

I was able to successfully delete the site.

I'm also able to delete a site with no purchases as normal.

Summary: From what I can see the PR is working as intended.

[westi]

LGTM and @KokkieH has very helpfully tested <3 🚀