feat(assets): add empty box placeholder image and update component reference

- Introduced a new empty box placeholder image to enhance the visual representation of empty states in the application.
- Updated the EmptyListPlaceholder component to reference the new image path, ensuring proper display in relevant contexts.

worklenz-frontend/src/components/EmptyListPlaceholder.tsx

@@ -8,7 +8,7 @@ type EmptyListPlaceholderProps = {
 };
 
 const EmptyListPlaceholder = ({
-  imageSrc = '/assets/images/empty-box.webp',
+  imageSrc = '/src/assets/images/empty-box.webp',
   imageHeight = 60,
   text,
 }: EmptyListPlaceholderProps) => {