fix: Nullable fields in processing_config (#1732)

Author: guptamyr

src/sagemaker/workflow/airflow.py

@@ -1154,10 +1154,11 @@ def processing_config(
     )
     config["ProcessingResources"] = processing_resources
 
-    stopping_condition = sagemaker.processing.ProcessingJob.prepare_stopping_condition(
-        processor.max_runtime_in_seconds
-    )
-    config["StoppingCondition"] = stopping_condition
+    if processor.max_runtime_in_seconds is not None:
+        stopping_condition = sagemaker.processing.ProcessingJob.prepare_stopping_condition(
+            processor.max_runtime_in_seconds
+        )
+        config["StoppingCondition"] = stopping_condition
 
     if processor.tags is not None:
         config["Tags"] = processor.tags
@@ -1174,4 +1175,6 @@ def input_output_list_converter(object_list):
     Returns:
         List of dicts
     """
-    return [obj._to_request_dict() for obj in object_list]
+    if object_list:
+        return [obj._to_request_dict() for obj in object_list]
+    return object_list