fix(query_row_optional): do not treat rows with NULL as missing rows

Instead of treating NULL type error
as absence of the row,
handle NULL values with SQL.
Previously we sometimes
accidentally treated a single column
being NULL as the lack of the whole row.

deltachat-jsonrpc/src/api/types/message.rs

@@ -640,7 +640,7 @@ pub struct MessageInfo {
     error: Option<String>,
     rfc724_mid: String,
     server_urls: Vec<String>,
-    hop_info: Option<String>,
+    hop_info: String,
 }
 
 impl MessageInfo {