Setup the store id attached to the customer on the admin index save test

Author: dmanners

dev/tests/integration/testsuite/Magento/Customer/Controller/Adminhtml/IndexTest.php

@@ -347,6 +347,7 @@ public function testSaveActionExistingCustomerUnsubscribeNewsletter()
                 'email' => '[email protected]',
                 'firstname' => 'test firstname',
                 'lastname' => 'test lastname',
+                'sendemail_store_id' => 1
             ],
             'subscription' => '0'
         ];