Support to send customer attribute to Alerta

While creating alerta alert, can we send customer attribute as defined in alerta's document https://docs.alerta.io/en/latest/cli.html#send-send-an-alert?

Start at the code path that creates an Alerta alert and compare its payload with Alerta's documented send-alert customer attribute. The issue is done when the configured customer attribute is included in alerts sent to Alerta and the existing alert flow still works.

Written by the indexing model from the issue text.