PERF: Don't bloat the Sidekiq queue with `Jobs::SendPushNotification`.

app/services/post_alerter.rb

@@ -415,6 +415,10 @@ class PostAlerter
   end
 
   def push_notification(user, payload)
+    if user.push_subscriptions.exists?
+      Jobs.enqueue(:send_push_notification, user_id: user.id, payload: payload)
+    end
+
     if SiteSetting.allow_user_api_key_scopes.split("|").include?("push") && SiteSetting.allowed_user_api_push_urls.present?
       clients = user.user_api_keys
         .where("('push' = ANY(scopes) OR 'notifications' = ANY(scopes)) AND push_url IS NOT NULL AND position(push_url in ?) > 0 AND revoked_at IS NULL",

config/initializers/100-push-notifications.rb

@@ -8,10 +8,6 @@ end
 
 SiteSetting.vapid_public_key_bytes = Base64.urlsafe_decode64(SiteSetting.vapid_public_key).bytes.join("|")
 
-DiscourseEvent.on(:post_notification_alert) do |user, payload|
-  Jobs.enqueue(:send_push_notification, user_id: user.id, payload: payload)
-end
-
 DiscourseEvent.on(:user_logged_out) do |user|
   PushNotificationPusher.clear_subscriptions(user)
 end