Show intro only on new install (but not when migrating from WP2)

Intro is marked as shown only when "Skip" or "Done" is explicitly used - this
avoids closing the intro by mistake and never having the option to see it again.

[MAILPOET-1446]

assets/js/src/intro.jsx

@@ -54,6 +54,18 @@ function Intro() {
     document.body.classList.remove('mailpoet-intro-active');
   });
 
+  intro.onskip(() => {
+    // this is called also when "Done" button used
+    MailPoet.Ajax.post({
+      api_version: window.mailpoet_api_version,
+      endpoint: 'settings',
+      action: 'set',
+      data: {
+        show_intro: 0,
+      },
+    });
+  });
+
   intro.start();
 }
 

lib/Config/Changelog.php

@@ -47,6 +47,7 @@ class Changelog {
         } else {
           $skip_wizard = WPHooks::applyFilters('mailpoet_skip_welcome_wizard', false);
           $redirect_url = $skip_wizard ? null : admin_url('admin.php?page=mailpoet-welcome-wizard');
+          Setting::setValue('show_intro', true);
         }
       }
     }

views/newsletters.html

@@ -305,6 +305,7 @@
 <% endblock %>
 
 <% block after_javascript %>
+<% if settings.show_intro %>
 <script>
   if (typeof olark !== 'undefined') {
     olark('api.box.onShow', function() {
@@ -318,4 +319,5 @@
     });
   }
 </script>
+<% endif %>
 <% endblock %>