rm sigma factor from cosine distribution

GUI/View/Instrument/DistributionEditor.cpp

@@ -63,7 +63,6 @@ void DistributionSelector::createDistributionWidgets()
         createMeanSpinBox(it->mean());
         createSpinBox(it->sigma());
         createNumSamplesSpinBox(it);
-        createSpinBox(it->sigmaFactor());
     } else if (auto* it = dynamic_cast<DistributionGateItem*>(m_item->distributionItem())) {
         auto* minSpinbox = createSpinBox(it->minimum());
         auto* maxSpinbox = createSpinBox(it->maximum());