SIENTIAPDE-1645: Update pod_id label retrieval in training activities to use HOSTNAME environment variable with localhost fallback.

model_manager/activities/training.py

@@ -302,7 +302,7 @@ class Training(SientiaMonitoring):
 
     def _get_training_labels(self, train_params: TrainModelParams) -> dict:
         return {
-            'pod_id': os.getenv('POD_ID'),
+            'pod_id': os.getenv('HOSTNAME', 'localhost'),
             'model_name': train_params.model_name,
             'model_type': train_params.model_type,
         }