feat: Dont update the drag image when converting an essential to a normal tab, b=no-bug, c=no-component

src/zen/drag-and-drop/ZenDragAndDrop.js

@@ -1270,9 +1270,6 @@
       const dt = event.dataTransfer;
       const draggedTab = event.dataTransfer.mozGetDataAt(TAB_DROP_TYPE, 0);
       if (draggedTab.hasAttribute("zen-essential")) {
-        setTimeout(() => {
-          dt.updateDragImage(...this.originalDragImageArgs);
-        }, 50);
         return;
       }
       const wrapper = this.originalDragImageArgs[0];