Add ownership verification steps to connection flow #6578831

Changes proposed in this Pull Request

In certain cases, we may want to request that users verify ownership of domains they want to connect to their site. This PR adds a flow to allow this when connecting a domain to a site with a paid plan.

When you are on a site that requires ownership verification, you will first be prompted to log in to your provider:

In the next step, you will be asked to enter the auth code for your domain:

Leaving the auth code field blank or entering an incorrect value will cause errors to be shown below the auth code field:

When the correct auth code is entered, the domain will be connected and the user will be directed to the “connect a domain flow” as usual.

Testing instructions

Hack the back end to return { ownership_verification_type: 'auth_code' } on the is-available endpoint.

Select a site that is on a paid plan and go through the “Use a domain I own” to connect a domain you already own that is not mapped to WordPress.com.

Try to verify the auth code without entering anything in the input field.
Try entering the incorrect auth code in the input field.
Make sure that your domain is properly connected when you enter the correct auth code.