Fix rounding in Slider component

Summary:
Changelog: [Internal]

There was a typo in condition. We need to be comparing step prop and not value. The same condition is implemented in Paper.

Reviewed By: JoshuaGross

Differential Revision: D23903493

fbshipit-source-id: 37506d0fac63f624332041602489ab1cf378bfcc

React/Fabric/Mounting/ComponentViews/Slider/RCTSliderComponentView.mm

@@ -300,7 +300,7 @@ - (void)onChange:(UISlider *)sender withContinuous:(BOOL)continuous
 
   const auto &props = *std::static_pointer_cast<const SliderProps>(_props);
 
-  if (props.step > 0 && value <= (props.maximumValue - props.minimumValue)) {
+  if (props.step > 0 && props.step <= (props.maximumValue - props.minimumValue)) {
     value = MAX(
         props.minimumValue,
         MIN(props.maximumValue, props.minimumValue + round((value - props.minimumValue) / props.step) * props.step));