Method to add a test email to the list.
https://api.wbsrvc.com/List/DeleteTestEmail/
POST
| user_key Required |
User Key of the user who initiates the call. Type: string |
| list_id Required |
ID of the list. Type: integer |
| test_email_id Required |
ID of the test email to delete. Type: integer |
| client_id Optional |
Client ID of the client in which the list is located. Type: integer |