[Bug Fix] Fix Firefox Page Drag Bug (#1837)

Fix a bug where the file drop prompt would show during page drag on Firefox.

Co-authored-by: kazandaki <[email protected]>

src/main/resources/static/js/multitool/DragDropManager.js

@@ -96,7 +96,8 @@ class DragDropManager {
   }
 
   adapt(div) {
-    const onDragStart = () => {
+    const onDragStart = (e) => {
+      e.preventDefault();
       this.startDraggingPage(div);
     };