Fix #16603 (#16605)

Fix issue #16603 undefined method `serialize_payload' for Unsuspend Account Service error.
It seems that this service forgot to `include Payloadable` so that `serialize_payload` could not be found in this service.

app/services/unsuspend_account_service.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 class UnsuspendAccountService < BaseService
+  include Payloadable
   def call(account)
     @account = account