Return error if send secret message result can't be resent.

GitOrigin-RevId: 354bf97c1a56c33fc1a30de9d054da84c9c68783

td/telegram/SecretChatActor.cpp

@@ -1710,6 +1710,9 @@ void SecretChatActor::on_outbound_outer_send_message_promise(uint64 state_id, Pr
   promise.set_value(Unit());  // Seems like this message is at least stored to binlog already
   if (state->send_result_) {
     state->send_result_({});
+  } else {
+    context_->on_send_message_error(state->message->random_id, Status::Error(400, "Message has already been sent"),
+                                    Auto());
   }
 }