Drawer: fix append to body (#21264)

packages/drawer/src/main.vue

@@ -190,6 +190,9 @@ export default {
     if (this.visible) {
       this.rendered = true;
       this.open();
+      if (this.appendToBody) {
+        document.body.appendChild(this.$el);
+      }
     }
   },
   destroyed() {