fix: Avoid auto-marking DSNs as seen; the user may want to see them in another MUA

Author: iequidoo

src/receive_imf.rs

@@ -1145,8 +1145,9 @@ async fn decide_chat_assignment(
         info!(context, "Message is an MDN (TRASH).");
         true
     } else if mime_parser.delivery_report.is_some() {
+        // Auto-marking DSNs as IMAP-seen should be avoided because the user may want to see them in
+        // another MUA.
         info!(context, "Message is a DSN (TRASH).");
-        markseen_on_imap_table(context, rfc724_mid).await.ok();
         true
     } else if mime_parser.get_header(HeaderDef::ChatEdit).is_some()
         || mime_parser.get_header(HeaderDef::ChatDelete).is_some()