MemberPress: Enable MailPoet Confirmation Email

By default, MailPoet will send the signup confirmation email to users. It will also prevent users from being added to the mailing list before they confirm the email address.

On the other hand, MemberPress will add users to the mailing list automatically when they register for a membership. Thus, under the MemberPress MailPoet Add-on settings, the option "Enable signup confirmation" should be set to "No" to avoid issues.

This code snippet will allow MailPoet to send the confirmation emails to users, and MemberPress to add users to the mailing list automatically upon registration.