Fix the missing variable in template script and incorrect port filter

[Pandede]

The following issues is resolved in the request:

1. There is a missing variable capDataLen in tm_template_script/arduino_image_provider.cpp
2. There is a port filter function in TM_Connector.pde, but it's incorrect on Linux platform - /dev/ttyACMx is a legitimate port for Arduino Nano 33 BLE Sense. However, the current filtering rule is too loose as I don't know the port name of other boards.