added pr_exclude to repeated failed test

Author: chandrakalahanchinal

app/code/Magento/Persistent/Test/Mftf/Test/StorefrontVerifyShoppingCartPersistenceTest.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
  /**
-  * Copyright © Magento, Inc. All rights reserved.
-  * See COPYING.txt for license details.
+  * Copyright 2025 Adobe
+  * All Rights Reserved.
   */
 -->
 
@@ -19,6 +19,7 @@
             <group value="persistent"/>
             <group value="customer"/>
             <group value="cloud"/>
+            <group value="pr_exclude"/>
         </annotations>
         <before>
             <!--Enable Persistence-->