Fix bug with log4j2 metrics not getting disabled

[jasonjkeller]

Fixes a bug where the below logic could evaluate to true even if application logging was disabled at the top level (i.e. application_logging.enabled: false):

        if (isApplicationLoggingEnabled() && getParent() == null || !isAdditive()) {...}

If the entire application_logging stanza is disabled at the top level it should result in all related features being disabled regardless of how they are set.

In this case, where the metrics feature is still enabled, the code would make it past the above logic and still generate logging metrics.

  application_logging:
    enabled: false
    forwarding:
      enabled: true
      max_samples_stored: 10000
    local_decorating:
      enabled: true
    metrics:
      enabled: true