qt: increase console command max length

src/qt/rpcconsole.cpp

@@ -468,6 +468,7 @@ RPCConsole::RPCConsole(interfaces::Node& node, const PlatformStyle *_platformSty
 
     // Install event filter for up and down arrow
     ui->lineEdit->installEventFilter(this);
+    ui->lineEdit->setMaxLength(16 * 1024 * 1024);
     ui->messagesWidget->installEventFilter(this);
 
     connect(ui->clearButton, &QPushButton::clicked, this, &RPCConsole::clear);