Slider - Increased hit target (#3531)

* Increased default thumb hit slop

* Added hitslop to Incubator.Slider thumb

* Added hitslop to all thumbs

* Removed extra const

* Removed extra line

* Revert old slider index changes

* Revert old slider index changes

Author: nitzanyiz

src/incubator/slider/Thumb.tsx

@@ -28,14 +28,21 @@ interface ThumbProps extends ViewProps {
 
 const SHADOW_RADIUS = 4;
 const THUMB_SIZE = 24;
+const THUMB_ACCESSIBLE_HITSLOP = Math.max(0, 48 - THUMB_SIZE) / 2;
+const DEFAULT_THUMB_HIT_SLOP = {
+  top: THUMB_ACCESSIBLE_HITSLOP,
+  bottom: THUMB_ACCESSIBLE_HITSLOP,
+  left: THUMB_ACCESSIBLE_HITSLOP,
+  right: THUMB_ACCESSIBLE_HITSLOP
+} as const;
 
 const Thumb = (props: ThumbProps) => {
   const {
     disabled,
     disableActiveStyling,
     activeStyle,
     defaultStyle,
-    hitSlop,
+    hitSlop = DEFAULT_THUMB_HIT_SLOP,
     onSeekStart,
     onSeekEnd,
     start,