ACP2E-279: Customer details are lost after editing an order.

Author: glo23503

app/code/Magento/Sales/Test/Unit/Plugin/Model/AdminOrder/GuestNameUpdateTest.php

@@ -113,8 +113,6 @@ public function testAfterCreateOrder()
             ->willReturn(2);
         $guestOrder->method('getCustomerIsGuest')
             ->willReturn(true);
-        $guestOrder->method('getCustomerIsGuest')
-            ->willReturnSelf();
 
         $updatedOrder = $this->guestNameUpdate->afterCreateOrder($subject, $guestOrder);