Event : add MemberId in TestEvent

Currently the memberId is missing in the Event structure of
TestEvent but memeberId
must be present in the Event structure as per DMTF schema

https://redfish.dmtf.org/schemas/v1/Event.v1_10_1.json

Therefore added MemberId in Test event structure.

Tested :
```
curl -k -u root:0penBmc -X POST /redfish/v1/EventService/Actions/
EventService.SubmitTestEvent -d '{"MessageId":""}'

Event received at the Redfish-Event-Listener

bodydata: {
  "@odata.type": "#Event.v1_4_0.Event",
  "Events": [
    {
      "Context": "",
      "EventId": "TestID",
      "EventTimestamp": "2024-08-13T08:14:56+00:00",
      "EventType": "Event",
      "MemberId": 0,
      "Message": "Generated test event",
      "MessageArgs": [],
      "MessageId": "OpenBMC.0.2.TestEventLog",
      "Severity": "OK"
    }
  ],
  "Id": "1",
  "Name": "Event Log"
}
```
Change-Id: I285e41ce377127fb1429f643e5068635384c7bfd
Signed-off-by: Chandramohan Harkude <chandramohan.harkude@gmail.com>
diff --git a/redfish-core/include/event_service_manager.hpp b/redfish-core/include/event_service_manager.hpp
index b004bde..f1903d4 100644
--- a/redfish-core/include/event_service_manager.hpp
+++ b/redfish-core/include/event_service_manager.hpp
@@ -380,6 +380,8 @@
         logEntryJson["Severity"] = log_entry::EventSeverity::OK;
         logEntryJson["Message"] = "Generated test event";
         logEntryJson["MessageId"] = "OpenBMC.0.2.TestEventLog";
+        // MemberId is 0 : since we are sending one event record.
+        logEntryJson["MemberId"] = 0;
         logEntryJson["MessageArgs"] = nlohmann::json::array();
         logEntryJson["EventTimestamp"] =
             redfish::time_utils::getDateTimeOffsetNow().first;