refactor: the `PreviewTextLazyLoad`-plugin must query `MessageItem` collections endpoint

... and provide additional `include`- and `options`-query parameters according to the update **rest-api-email**-specs:

```http
GET MailAccounts/1/MailFolders/INBOX/MessageItems?fields[MessageItem]=id&include=MessageBody&fields[MessageBody]=textHtml,textPlain&options[MessageBody]={"textHtml":{"length":200}, "textPlain": {"length": 200}} HTTP/1.1
Content-Type: application/vnd.api+json
```