🐛 Fixed suppression list data for emails with plus sign (#16140)

no issue

When fetching the suppression list data for emails with a plus sign, the
parsing of the NQL filter fails:

```at Child.applyDefaultAndCustomFilters (/Ghost/node_modules/@tryghost/bookshelf-filter/lib/bookshelf-filter.js:66:23)
[ghost] email:[simon+test@ghos
[ghost] ------------^
[ghost] Expecting 'OR', 'RBRACKET', got 'AND'
```

ghost/core/core/server/services/email-suppression-list/MailgunEmailSuppressionList.js

@@ -73,7 +73,7 @@ class MailgunEmailSuppressionList extends AbstractEmailSuppressionList {
 
         try {
             const collection = await this.Suppression.findAll({
-                filter: `email:[${emails.join(',')}]`
+                filter: `email:[${emails.map(email => `'${email}'`).join(',')}]`
             });
 
             return emails.map((email) => {