Private Mode Broken

## Describe the bug

Since the last update, the privacy mode seems to be slightly broken. Before, when enabled, it would not disclose any information on the sending SMTP server, now it does partially or fully depending on what mode is set.

With privacy mode enabled the headers appear like:

```
Received: by postal.host with SMTP; Mon, 20 May 2024 16:00:21 +0000
Received: from sending.host (localhost [IPv6:::1]) by sending.host (Postfix) with ESMTPS id 0C222B2F05 for ; Mon, 20 May 2024 16:00:21 +0000
```

but with it disabled they appear like:

```
Received: from sending.host (sending.host [2001:xx:xx::xx]) by postal.host with SMTP; Mon, 20 May 2024 15:58:03 +0000
Received: from sending.host (localhost [IPv6:::1]) by sending.host (Postfix) with ESMTPS id 9EFA011D194 for ; Mon, 20 May 2024 15:58:02 +0000
```

It used to only ever show:

```
Received: by postal.host with SMTP; Mon, 20 May 2024 16:00:21 +0000
```