fix: enableEnhancedBootstrapGrid inserts the rowWrapperNode at the en…

…d of the stage instead of using the last position causing controls to always be inserted at the end even if prepend option is set. Use the location of the added Field's LI to append the rowWrapper before moving the LI within the row

src/js/form-builder.js

@@ -1197,7 +1197,7 @@ function FormBuilder(opts, element, $) {
 
       //If inserting, use the existing index, do not always append to end
       if (!insertingNewControl) {
-        $stage.append(rowWrapperNode)
+        $li.after(rowWrapperNode)
       }
 
       $li.appendTo(colWrapperNode)