revert: "fix: External node offset was shifted"

This reverts commit 7bfe115.

Author: fritz-c

src/utils/drag-and-drop-utils.js

@@ -51,9 +51,7 @@ function getTargetDepth(dropTargetProps, monitor, component) {
     if (component) {
       const relativePosition = findDOMNode(component).getBoundingClientRect(); // eslint-disable-line react/no-find-dom-node
       const leftShift =
-        monitor.getSourceClientOffset().x -
-        monitor.getInitialSourceClientOffset().x -
-        relativePosition.left;
+        monitor.getSourceClientOffset().x - relativePosition.left;
       blocksOffset = Math.round(
         leftShift / dropTargetProps.scaffoldBlockPxWidth
       );