Exra member in STATUS_AGENT_Payload

[jseldent]

Micro-XRCE-DDS adds an extra result member before agent_info in STATUS_AGENT_Payload. According to the official dds_xrce_types.idl, it should be

    @extensibility(FINAL)
    struct STATUS_AGENT_Payload {
        AGENT_Representation agent_info;
    };

but an actual STATUS_AGENT message looks like

with the extra result member highlighted.

[pablogs9]

Added to 3.0.0 milestone