Remove dead code - replace with comment

Author: jason-fox

lib/services/ngsi/ngsiService.js

@@ -688,13 +688,11 @@ function formatAsNGSILD(json){
                 obj[key] = json[key];
                 break;
            case constants.TIMESTAMP_ATTRIBUTE:
-                /*               
-                var timestamp = json[constants.TIMESTAMP_ATTRIBUTE].value;
-                if(timestamp ===  constants.ATTRIBUTE_DEFAULT || !(moment(timestamp).isValid())){
-                    obj.observedAt = constants.DATETIME_DEFAULT;
-                } else {
-                    obj.observedAt = moment.tz(timestamp, 'Etc/UTC').toISOString();
-                }*/
+                /* 
+                    The NGSIv2 timestamp attribute (if it exists) should not be processed here
+                    as it will be removed. The equivalent NGSI-LD observedAt is treated as a simple 
+                    string, not a standard NGSI-LD Property.
+                */
                 break;
             default:
                 obj[key] = convertNGSIv2ToLD(json[key]);