Add Datalake GCS metrics to prometheus default exporter (#23155)

Author: kodjo-anipah

graylog2-server/src/main/resources/prometheus-exporter.yml

@@ -1301,6 +1301,16 @@ metric_mappings:
   - metric_name: "data_warehouse_iceberg_file_io_local_read"
     match_pattern: "org.graylog.iceberg.file.io.local.read"
 
+  - metric_name: "data_warehouse_iceberg_file_io_gcs_write"
+    match_pattern: "org.graylog.iceberg.file.io.gcs.write.*"
+    wildcard_extract_labels:
+      - "write"
+
+  - metric_name: "data_warehouse_iceberg_file_io_gcs_read"
+    match_pattern: "org.graylog.iceberg.file.io.gcs.read.*"
+    wildcard_extract_labels:
+      - "read"
+
   - metric_name: "data_warehouse_journal_writer_written_messages"
     match_pattern: "org.graylog.plugins.datawarehouse.output.DataWarehouseJournalWriter.written-messages"