fix: config-provider throw error when use [email protected]

Author: tangjinzhou

components/config-provider/index.jsx

@@ -54,7 +54,7 @@ const ConfigProvider = {
     },
   },
   render() {
-    return this.$slots.default ? filterEmpty(this.$slots.default) : null;
+    return this.$slots.default ? filterEmpty(this.$slots.default)[0] : null;
   },
 };