Changes to GET /api/v1.0/maildomains

the response property results/items/expected_dns_records became nullable for the status 200

the results/items/expected_dns_records response's property type changed from string to array for status 200

added the new optional query request parameter q

added the required property results/items/mailbox_count to the response with the 200 status

added the required property results/items/identity_sync to the response with the 200 status