feat: Extract reward_lambda_arn from Nova recipes to training job hyperparameters

[malav-shastri]

…erparameters

Issue #, if available:

Description of changes:
This PR adds support for extracting reward_lambda_arn from Nova recipe files and passing it as a hyperparameter to SageMaker training jobs

Changes made:

• src/sagemaker/modules/train/sm_recipes/utils.py: Added reward_lambda_arn extraction in _get_args_from_nova_recipe() for ModelTrainer code path
• src/sagemaker/pytorch/estimator.py: Added reward_lambda_arn extraction in _setup_for_nova_recipe() for PyTorch Estimator code path
• tests/unit/test_pytorch_nova.py: Added comprehensive test coverage following existing eval_lambda_arn test patterns
• tests/unit/sagemaker/modules/train/sm_recipes/test_utils.py: Existing test coverage for utils.py path

Testing done:
Unit tests added:

• test_setup_for_nova_recipe_with_reward_lambda() - verifies successful extraction in PyTorch estimator
• test_setup_for_nova_recipe_without_reward_lambda() - verifies no extraction when parameter absent
• Existing test_get_args_from_nova_recipe_with_reward_lambda() - verifies ModelTrainer path

Merge Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your pull request.

General

• I have read the CONTRIBUTING doc
• I certify that the changes I am introducing will be backward compatible, and I have discussed concerns about this, if any, with the Python SDK team
• I used the commit message format described in CONTRIBUTING
• I have passed the region in to all S3 and STS clients that I've initialized as part of this change.
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added unit and/or integration tests as appropriate to ensure backward compatibility of the changes
• I have checked that my tests are not configured for a specific region or account (if appropriate)
• I have used unique_name_from_base to create resource names in integ tests (if appropriate)
• If adding any dependency in requirements.txt files, I have spell checked and ensured they exist in PyPi

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[zhaoqizqwang]

Hi, as part of incoming PySDK V3 release, we request you to change the target branch to master-v2. Master branch will only contain incoming v3 source code