`disabled_transport_categories` setting on an audit logging config may be unnecessary after transport client removal

Since OpenSearch 2.0, support for the transport client has been removed. The transport client was removed from the security plugin in this PR: https://github.com/opensearch-project/security/pull/1701

My understanding of disabled_transport_categories is that it is used to enable an audit logging to log events from originating from the transport client.

Below is an example of a audit logging config of the security plugin's audit.yml file from the demo configuration:

config:
  # enable/disable audit logging
  enabled: true

  audit:
    # Enable/disable REST API auditing
    enable_rest: true

    # Categories to exclude from REST API auditing
    disabled_rest_categories:
      - AUTHENTICATED
      - GRANTED_PRIVILEGES

    # Enable/disable Transport API auditing
    enable_transport: true

    # Categories to exclude from Transport API auditing
    disabled_transport_categories:
      - AUTHENTICATED
      - GRANTED_PRIVILEGES

The disabled_transport_categories setting may not be needed here after the TransportClient's removal.

First: Determine if it is safe to remove values from settings.
Second: If safe to remove, remove. If not, update documentation.

Start with config/audit.yml and the transport-client removal PR linked in the issue, then trace whether disabled_transport_categories is still consumed by the security plugin. Done means confirming the setting's compatibility and either removing the obsolete configuration and references or updating its documentation; run the relevant audit-logging tests if the repository identifies them.