fix random high reading of the strain sensor

[brushknight]

Sometimes strain sensor gives random high readings and then goes back to normal values. It triggers the ghost press of the knob which is annoying.

Proposed solution: Add a filter that detects those spikes, filters them out, and returns the previous value.

[carlhampuswall]

Partly fixed with new strain calibration implementation. Will verify in coming days.

[carlhampuswall]

Is better now, but stills needs further work.