do not unarchive one-to-one on receiving read-receipts

src/dc_receive_imf.rs

@@ -772,9 +772,6 @@ async fn add_parts(
 
     *sent_timestamp = std::cmp::min(*sent_timestamp, rcvd_timestamp);
 
-    // unarchive chat
-    chat_id.unarchive(context).await?;
-
     // if the mime-headers should be saved, find out its size
     // (the mime-header ends with an empty line)
     let save_mime_headers = context.get_config_bool(Config::SaveMimeHeaders).await;
@@ -896,6 +893,10 @@ async fn add_parts(
         *insert_msg_id = *id;
     }
 
+    if !is_hidden {
+        chat_id.unarchive(context).await?;
+    }
+
     *hidden = is_hidden;
     created_db_entries.extend(ids.iter().map(|id| (chat_id, *id)));
     mime_parser.parts = new_parts;