fix(dnd): dont use classname (jquense#2232)

allow for className object usage

src/addons/dragAndDrop/EventWrapper.js

@@ -42,7 +42,9 @@ class EventWrapper extends React.Component {
     // hack: because of the way the anchors are arranged in the DOM, resize
     // anchor events will bubble up to the move anchor listener. Don't start
     // move operations when we're on a resize anchor.
-    const isResizeHandle = e.target.className.includes('rbc-addons-dnd-resize')
+    const isResizeHandle = e.target
+      .getAttribute('class')
+      ?.includes('rbc-addons-dnd-resize')
     if (!isResizeHandle)
       this.context.draggable.onBeginAction(this.props.event, 'move')
   }