avoid circular parsing for observiq-agent and bindplane-agent

[jsirianni]

This change allows the openshift plugin to avoid parsing log agent logs from the observiq-agent and bindplane-agent. These agents do not currently write to stdout / stderr but it is possible they will in the future. It is also possible that some users convert from bindplane / observiq agents to stanza for headless configuration. This conversion will likely retain the original pod names.

We already drop output from pods matching stanza

      # Ignore logs written by Stanza to avoid circular parsing
      - expr: '$record._COMM == "dockerd-current" and $record.CONTAINER_NAME != nil and $record.CONTAINER_NAME matches "stanza"'
        output: drop_output