fix types

Author: tru-kilo

webview-ui/src/components/chat/TaskHeader.tsx

@@ -141,8 +141,8 @@ const TaskHeader = ({
 								{highlightText(task.text, false, customModes)}
 							</div>
 						</div>
-						{(task.images && task.images.length > 0 ||task.files && task.files.length > 0) && (
-							<Thumbnails images={task.images} files={task.files} />
+						{((task.images && task.images.length > 0) || (task.files && task.files.length > 0)) && (
+							<Thumbnails images={task.images ?? []} files={task.files ?? []} />
 						)}
 
 						<div className="flex flex-col gap-1">