Serial device detection broken on Linux

[oCanna]

• I confirm that this is an issue rather than a question.

Bug report

[hyperiond LEDDEVICE] LedDevice 'adalight' found.
[hyperiond LEDDEVICE] Opening UART: /dev/ttyACM0
[hyperiond LEDDEVICE] Device disabled, device 'adalight' signals error: 'Invalid serial device name: [/dev/ttyACM0]!'
[hyperiond LEDDEVICE] Device disabled, device 'adalight' signals error: 'Error opening device!'

The serial device detection was working prior this commit: e365a28

Steps to reproduce

On a linux system, try to connect led hardware through a serial interface.

What is expected?

A working serial device detection.

What is actually happening?

ping @heikobihr

System

Hyperion Server:

• Build: master (GitHub-922420bb/6cf9dfaa-1593464112)
• Build time: Jul 5 2020 16:42:12
• Git Remote: https://github.com/hyperion-project/hyperion.ng.git
• Version: 2.0.0-alpha.6
• UI Lang: auto (BrowserLang: de)
• UI Access: expert
• Avail Capt: v4l2,framebuffer,x11,qt

Hyperion Server OS:

• Distribution: Ubuntu 20.04 LTS
• Arch: x86_64
• Kernel: linux (5.4.0-40-generic (WS: 64))
• Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0

[Lord-Grey]

Duplicate to #859, Fix is part of #855.
Immediate workaround is just using the portable without /dev/, i.e. ttyACM0 only.