Do not exchange XMPP contacts when turned off by inviter

app/models/user.rb

@@ -63,7 +63,10 @@ class User < ApplicationRecord
     return if Rails.env.development?
 
     if inviter.present?
-      exchange_xmpp_contact_with_inviter if Setting.ejabberd_enabled?
+      if Setting.ejabberd_enabled? &&
+          inviter.pref_enabled?("xmpp:exchange_contacts_with_invitees")
+        exchange_xmpp_contact_with_inviter
+      end
     end
   end