Fix the build.

lib/discourse_chat/provider/telegram/telegram_initializer.rb

@@ -1,13 +1,22 @@
 # frozen_string_literal: true
 
-event =
 if Gem::Version.new(Discourse::VERSION::STRING) > Gem::Version.new("2.3.0.beta8")
-    :site_setting_changed
+  DiscourseEvent.on(:site_setting_changed) do |setting_name, old_value, new_value|
-  else
+    isEnabledSetting = setting_name == 'chat_integration_telegram_enabled'
-    :site_setting_saved
+    isAccessToken =  setting_name == 'chat_integration_telegram_access_token'
-  end
 
-DiscourseEvent.on(event) do |sitesetting|
+    if (isEnabledSetting || isAccessToken)
+      enabled = isEnabledSetting ? new_value == true : SiteSetting.chat_integration_telegram_enabled
+
+      if enabled
+        Scheduler::Defer.later("Setup Telegram Webhook") do
+          DiscourseChat::Provider::TelegramProvider.setup_webhook()
+        end
+      end
+    end
+  end
+else
+  DiscourseEvent.on(site_setting_saved) do |sitesetting|
     isEnabledSetting = sitesetting.name == 'chat_integration_telegram_enabled'
     isAccessToken =  sitesetting.name == 'chat_integration_telegram_access_token'
 
@@ -20,3 +29,4 @@ DiscourseEvent.on(event) do |sitesetting|
       end
     end
   end
+end