Allow lower values for touch threshold

[RobinMeis]

Solved issue #4076 by allowing lower values for touch threshold

[blazoncek]

Once @DedeHai gets back from vacation I hope he'll review and approve.

[DedeHai]

Need to test, may lead to ghost detections

[RobinMeis]

Need to test, may lead to ghost detections

For me it doesn't but shouldn't be a too big issue as you already can get ghost detections on ESP32-Wroom with inappropriate settings.

[DedeHai]

I tested the change, low values lead to ghost detections but that is probably ok, I did not notice any crashes in my tests (tested on S2).
@RobinMeis your PR is missing changes to the second interrupt attachment here:

WLED/wled00/set.cpp

Line 292 in f6c47ac

touchAttachInterrupt(btnPin[i], touchButtonISR, 256 + (touchThreshold << 4)); // threshold on Touch V2 is much higher (1500 is a value given by Espressif example, I measured changes of over 5000)

apart from that I am ok with removing the 256 as a minimum base value.

[RobinMeis]

I have fixed this. For me, I also get ghost detections for very low values but didn't get any ghost detections within the last two weeks on two lamps with reasonable values.

[DedeHai]

looks good, gets my approval.