🐛 Fix serial_data_available (#23160)

Marlin/src/gcode/queue.cpp

 
 static bool serial_data_available(serial_index_t index) {
   const int a = SERIAL_IMPL.available(index);
-  #if BOTH(RX_BUFFER_MONITOR, RX_BUFFER_SIZE)
+  #if ENABLED(RX_BUFFER_MONITOR) && RX_BUFFER_SIZE
     if (a > RX_BUFFER_SIZE - 2) {
       PORT_REDIRECT(SERIAL_PORTMASK(index));
       SERIAL_ERROR_MSG("RX BUF overflow, increase RX_BUFFER_SIZE: ", a);