Previously, the `send_message` method always queried for an existing non-final
message to update, even when `is_final=True`. This caused unnecessary database
lookups and could incorrectly attempt to update a stale message when sending
a final version. The fix wraps the continuation check inside `if not is_final:`,
so the lookup and update path is only taken when the message is explicitly
marked as non-final.
retoor
fd7fc4220c