Use refreshMSSKeyStatus in preview modal to refresh key status

[MAILPOET-4633]

mailpoet/assets/js/src/newsletter_editor/components/save.js

@@ -758,10 +758,7 @@ Module.NewsletterPreviewView = Marionette.View.extend({
     return MailPoet.Ajax.post({
       api_version: window.mailpoet_api_version,
       endpoint: 'services',
-      action: 'checkMSSKey',
-      data: {
-        key: window.mailpoet_api_key,
-      },
+      action: 'refreshMSSKeyStatus',
     })
       .done((response) => {
         this.model.set('awaitingKeyCheck', false);

mailpoet/views/newsletter/editor.html

@@ -374,7 +374,6 @@
   var mailpoet_email_editor_tutorial_seen  = '<%= editor_tutorial_seen %>';
   var mailpoet_email_editor_tutorial_url = '<%= cdn_url('newsletter-editor/editor-drag-demo.20190226-1505.mp4') %>';
   var mailpoet_installed_at = '<%= settings.installed_at %>';
-  var mailpoet_api_key = '<%= settings.mta.mailpoet_api_key %>';
 </script>
 
 <% endblock %>