fix: style value not remove when become undefined

src/runtime/internal/dom.ts

@@ -641,7 +641,7 @@ export function set_input_type(input, type) {
 }
 
 export function set_style(node, key, value, important) {
-	if (value === null) {
+	if (value === null || value === undefined) {
 		node.style.removeProperty(key);
 	} else {
 		node.style.setProperty(key, value, important ? 'important' : '');