update mapping json obeservsi dan diagnosis report

internal/satusehat/usecase/diagnosticreport/mapper.go

@@ -120,5 +120,13 @@ func MapRequestToFHIR(req DiagnosticReportRequest) satusehat.FHIRPayload {
 		payload.Set("conclusion", req.Conclusion)
 	}
 
+	if req.ObservationID != "" {
+		payload.Set("observation", map[string]interface{}{"reference": "Observation/" + req.ObservationID})
+	}
+
+	if req.ServiceRequestID != "" {
+		payload.Set("serviceRequest", map[string]interface{}{"reference": "ServiceRequest/" + req.ServiceRequestID})
+	}
+
 	return payload
 }