B2B-2133: [AWS S3] Test Fails to Assert Success Message after adding to cart

 - Fixing flakiness

Author: dhaecker

app/code/Magento/Checkout/Test/Mftf/ActionGroup/GuestCheckoutFillingShippingSectionActionGroup.xml

@@ -28,8 +28,9 @@
         <selectOption selector="{{CheckoutShippingSection.region}}" userInput="{{customerAddressVar.state}}" stepKey="selectRegion"/>
         <fillField selector="{{CheckoutShippingSection.postcode}}" userInput="{{customerAddressVar.postcode}}" stepKey="enterPostcode"/>
         <fillField selector="{{CheckoutShippingSection.telephone}}" userInput="{{customerAddressVar.telephone}}" stepKey="enterTelephone"/>
-        <waitForLoadingMaskToDisappear stepKey="waitForLoadingMask"/>
+        <waitForPageLoad stepKey="waitForLoadingMask"/>
         <waitForElement selector="{{CheckoutShippingMethodsSection.checkShippingMethodByName('shippingMethod')}}" stepKey="waitForShippingMethod"/>
+        <waitForPageLoad stepKey="waitForPageLoad"/>
         <click selector="{{CheckoutShippingMethodsSection.checkShippingMethodByName('shippingMethod')}}" stepKey="selectShippingMethod"/>
         <waitForElement selector="{{CheckoutShippingSection.next}}" time="30" stepKey="waitForNextButton"/>
         <click selector="{{CheckoutShippingSection.next}}" stepKey="clickNext"/>