FIX: Trigger user_logged_out event when the user logs out (#28482)

What did this fix?
===============

Previously, we only triggered this event in the `user.logged_out` method.
This resulted in the event being triggered only when the user was logged
out by the administrator or the site had strict logout mode enabled.
This bug affected customers who managed user status via webhooks.

meta topic: https://meta.discourse.org/t/user-log-out-event-not-triggered-in-webhooks/249464

lib/auth/default_current_user_provider.rb

@@ -338,6 +338,7 @@ class Auth::DefaultCurrentUserProvider
       user.logged_out
     elsif user && @user_token
       @user_token.destroy
+      DiscourseEvent.trigger(:user_logged_out, user)
     end
 
     cookie_jar.delete("authentication_data")