fix(sortable): Prevent touchscreen scrolling conflict via touch-action (

#4227)

Fixes #4178.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

src/core/components/sortable/sortable.less

@@ -70,6 +70,7 @@
 .sortable-enabled li:not(.no-sorting):not(.disallow-sorting) {
   .sortable-handler {
     pointer-events: auto;
+    touch-action: none;
     opacity: 1;
     &:after {
       transform: translateX(0px);