MAGETWO-66489: Fatal Error Previewing Registry Update Email

- Update automated test

Author: nikshostko

app/code/Magento/Email/Test/Mftf/ActionGroup/EmailTemplateActionGroup.xml

@@ -20,6 +20,7 @@
         <!--Fill in required fields in "Template Information" tab and click "Save Template" button-->
         <click stepKey="clickLoadTemplateButton" selector="{{EmailTemplatesSection.loadTemplateButton}}" after="selectValueFromTemplateDropDown"/>
         <fillField stepKey="fillTemplateNameField" selector="{{EmailTemplatesSection.templateNameField}}" userInput="{{EmailTemplate.templateName}}" after="clickLoadTemplateButton"/>
+        <waitForLoadingMaskToDisappear stepKey="wait1"/>
         <click stepKey="clickSaveTemplateButton" selector="{{EmailTemplatesSection.saveTemplateButton}}"/>
         <waitForPageLoad stepKey="waitForNewTemplateCreated"/>
     </actionGroup>