BUGFIX: Actually detect if sensor isn't connected

ampel-firmware/src/lib/S8_UART/s8_uart.cpp

@@ -561,6 +561,7 @@ uint8_t S8_UART::serial_read_bytes(uint8_t max_bytes, uint32_t timeout_ms) {
                 nb = mySerial->readBytes(buf_msg, max_bytes);
                 readed = true;
             }
+            delay(50); //NOTE: ESP crashes without this delay, possibly because it calls readBytes too many times, too fast
             end_t = millis();
         }