fix: jumpstart docs network isolation (#2989)

Author: evakravi

doc/overview.rst

@@ -757,6 +757,7 @@ see `Model <https://sagemaker.readthedocs.io/en/stable/api/inference/model.html
        entry_point="inference.py",
        role=Session().get_caller_identity_arn(),
        predictor_cls=Predictor,
+       enable_network_isolation=True,
    )
 
 Save the output from deploying the model to a variable named
@@ -874,6 +875,7 @@ value is not set.
        hyperparameters=default_hyperparameters,
        instance_count=instance_count,
        instance_type=training_instance_type,
+       enable_network_isolation=True,
    )
 
    # Specify the S3 location of training data for the training channel
@@ -935,6 +937,7 @@ took your model to train.
        image_uri=deploy_image_uri,
        source_dir=deploy_script_uri,
        endpoint_name=endpoint_name,
+       enable_network_isolation=True,
    )
 
 Perform Inference on a SageMaker Endpoint