MAGETWO-48084: [FT] Update ExpressCheckoutOnePageTest according to new PayPal registration steps

- added TO_MAINTAIN for PayPal Express Checkout tests

Author: Elena Marchenko

dev/tests/functional/tests/app/Magento/Paypal/Test/TestCase/ExpressCheckoutFromProductPageTest.php

@@ -31,6 +31,7 @@ class ExpressCheckoutFromProductPageTest extends Scenario
     const MVP = 'yes';
     const DOMAIN = 'CS';
     const TEST_TYPE = '3rd_party_test';
+    const TO_MAINTAIN = 'yes';
     /* end tags */
 
     /**

dev/tests/functional/tests/app/Magento/Paypal/Test/TestCase/ExpressCheckoutFromShoppingCartTest.php

@@ -31,6 +31,7 @@ class ExpressCheckoutFromShoppingCartTest extends Scenario
     const MVP = 'yes';
     const DOMAIN = 'CS';
     const TEST_TYPE = '3rd_party_test';
+    const TO_MAINTAIN = 'yes';
     /* end tags */
 
     /**

dev/tests/functional/tests/app/Magento/Paypal/Test/TestCase/ExpressCheckoutOnePageTest.php

@@ -35,6 +35,7 @@ class ExpressCheckoutOnePageTest extends Scenario
     const MVP = 'yes';
     const DOMAIN = 'CS';
     const TEST_TYPE = '3rd_party_test';
+    const TO_MAINTAIN = 'yes';
     /* end tags */
 
     /**

dev/tests/functional/tests/app/Magento/Paypal/Test/TestCase/InContextExpressCheckoutFromShoppingCartTest.php

@@ -32,6 +32,7 @@ class InContextExpressCheckoutFromShoppingCartTest extends Scenario
     const MVP = 'yes';
     const DOMAIN = 'CS';
     const TEST_TYPE = '3rd_party_test';
+    const TO_MAINTAIN = 'yes';
     /* end tags */
 
     /**

dev/tests/functional/tests/app/Magento/Paypal/Test/TestCase/InContextExpressOnePageCheckoutTest.php

@@ -32,6 +32,7 @@ class InContextExpressOnePageCheckoutTest extends Scenario
     const MVP = 'yes';
     const DOMAIN = 'CS';
     const TEST_TYPE = '3rd_party_test';
+    const TO_MAINTAIN = 'yes';
     /* end tags */
 
     /**