fix: alert query for null trace id in sample dataset (#1382)

- Updated the alert for "Trace ID null" to correctly detect 
JSON null values instead of empty strings in the "trace_id" column.
- Renamed the alert from "Trace ID or Span ID null" to "Trace ID null" for clarity.

Author: nikhilsinhaparseable

resources/ingest_demo_data.sh

@@ -436,9 +436,8 @@ create_alerts() {
         echo "Response: $response2"
     fi
 
-    # Alert 3: Trace ID or Span ID null
-    alert3_json="{\"severity\":\"high\",\"title\":\"Trace ID or Span ID null\",\"stream\":\"$P_STREAM\",\"alertType\":\"threshold\",\"aggregates\":{\"aggregateConfig\":[{\"aggregateFunction\":\"count\",\"conditions\":{\"operator\":null,\"conditionConfig\":[{\"column\":\"trace_id\",\"operator\":\"is null\",\"value\":\"\"}]},\"column\":\"trace_id\",\"operator\":\">\",\"value\":0}]},\"evalConfig\":{\"rollingWindow\":{\"evalStart\":\"5h\",\"evalEnd\":\"now\",\"evalFrequency\":1}},\"targets\":[\"$target_id\"]}"
-    
+    # Alert 3: Trace ID null
+    alert3_json="{\"severity\":\"high\",\"title\":\"Trace ID null\",\"stream\":\"$P_STREAM\",\"alertType\":\"threshold\",\"aggregates\":{\"aggregateConfig\":[{\"aggregateFunction\":\"count\",\"conditions\":{\"operator\":null,\"conditionConfig\":[{\"column\":\"trace_id\",\"operator\":\"is null\",\"value\":null}]},\"column\":\"trace_id\",\"operator\":\">\",\"value\":0}]},\"evalConfig\":{\"rollingWindow\":{\"evalStart\":\"5h\",\"evalEnd\":\"now\",\"evalFrequency\":1}},\"targets\":[\"$target_id\"]}"
     response3=$(curl_with_retry "$P_URL/api/v1/alerts" "POST" "$alert3_json" "application/json" 3)
     if [[ $? -eq 0 ]]; then
         echo "Alert 3 (Trace ID null) created successfully"