[Documentation] Setup guide recommends the deprecated Filebeat `log` input instead of the new `filestream` input

The [ECS Logging Java Setup](https://www.elastic.co/guide/en/ecs-logging/java/current/setup.html) recommends the Filebeat [`log` input](https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-input-log.html) that is deprecated since 7.16 in favor of the [`filestream` input](https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-input-filestream.html)