Rodrigo Primo c507229dd2 Add unsubscribe API method ...

It can be used by calling:

```
$mailpoet_api = \MailPoet\API\API::MP('v1');
$mailpoet_api->unsubscribe($subscriberId);
```

[MAILPOET-5152]

2023-03-27 19:25:49 +02:00

..

v1

Add unsubscribe API method

2023-03-27 19:25:49 +02:00