#6868435 Emails: Thank you page for Professional Email when buying domain

Changes proposed in this Pull Request

This Pull Request adds the necessary code to show Thank You component after checking out a Domain with a Professional Email.

Testing instructions

Test 1

1. Go to Upgrades -> Domains
2. Click on the button Add a domain for this site -> Search for a domain
3. When asked to add an Email, fill in necessary fields and click “Add”
4. Buy with credits

Expected result
You should see a Thank you page, congratulating the purchase of the domain with CTA’s to go to Inbox.

Test 2

1. Go to Upgrades -> Domains
2. Click on the button Add a domain for this site -> Search for a domain
3. When asked to add an Email, press the SKIP button
4. Buy with credits

Expected result
You should see a Thank you page, congratulating the purchase of the domain with CTA’s to add professional email.

Test 3

0. Have an external domain on a domain provider different than WPCOM.
1. Go to Upgrades -> Domains
2. Click on the button Add a domain for this site -> Use a domain I own
3. Buy with credits

REMARKS
If you are not allowed to map domains to the site, you need to sandbox and change the function: function is_exempt_from_domains_with_plans_only( $current_user = false ) to return always true

Expected result
You should see a Thank you page, congratulating the purchase of the domain mapping with CTA’s to add professional email.

Test 4, regression test

1. Go to Upgrades -> domains
2. Click on the button Add a domain for this site -> Use a domain I own
3. Type the domain you own and start a transfer domain
4. But with credits

Expected result
You should see a thank you page, congratulating about the domain being transferred like this:

Test 5
Repeat those tests where you have bought Professional Email, but this time buy a Google Workspace, then the thank you page shouldn’t have the step to go to inbox.

Example:

REMARKS
Thank you component shown in Test 1 & 2 will replace the old one below
It will replace this thank you page:

Related to {1200182182542585-as-1201102838390955}