[fix] check parentNode exists before removing child (#6910)

Fixes #6037

src/runtime/internal/dom.ts

@@ -204,7 +204,9 @@ export function insert_hydration(target: NodeEx, node: NodeEx, anchor?: NodeEx)
 }
 
 export function detach(node: Node) {
-	node.parentNode.removeChild(node);
+	if (node.parentNode) {
+		node.parentNode.removeChild(node);
+	}
 }
 
 export function destroy_each(iterations, detaching) {