docs:fix full-screen modal on the presentation documentation has no effect (#6905)

Author: 24min

components/modal/demo/fullscreen.vue

@@ -45,7 +45,7 @@ const handleOk = (e: MouseEvent) => {
   open.value = false;
 };
 </script>
-<style lang="less" scoped>
+<style lang="less">
 .full-modal {
   .ant-modal {
     max-width: 100%;