Update WidgetLayout.astro (#333)

防止重复注册报错

src/components/widget/WidgetLayout.astro

@@ -54,5 +54,7 @@ const className = Astro.props.class
         }
     }
 
-    customElements.define('widget-layout', WidgetLayout);
-</script>
+    if (!customElements.get("widget-layout")) {
+        customElements.define("widget-layout", WidgetLayout);
+    }
+</script>