Mute notifications for demo site.

app/Notifications/Test/OwnerTestNotificationEmail.php

@@ -25,6 +25,7 @@ declare(strict_types=1);
 namespace FireflyIII\Notifications\Test;
 
 use FireflyIII\Notifications\Notifiables\OwnerNotifiable;
+use FireflyIII\Support\Facades\FireflyConfig;
 use Illuminate\Bus\Queueable;
 use Illuminate\Notifications\Messages\MailMessage;
 use Illuminate\Notifications\Notification;
@@ -63,6 +64,10 @@ class OwnerTestNotificationEmail extends Notification
      */
     public function via(OwnerNotifiable $notifiable): array
     {
+        $isDemoSite  = FireflyConfig::get('is_demo_site');
+        if(true === $isDemoSite) {
+            return [];
+        }
         return ['mail'];
     }
 }