fix: refresh MTRL attached-job test fixtures (#6259)

Update both MTRL attached-job integration paths to use a completed training job with an available model package. The previous fixture outputs no longer support the current evaluation flow.

This restores attachment, fine-tuned evaluation, and metrics coverage.

Author: papriwal

sagemaker-train/tests/integ/train/test_mtrl_evaluator_3p_agent.py

@@ -317,7 +317,7 @@ def test_evaluate_with_attached_trainer(self, lambda_agent_arn, test_config):
         from sagemaker.train.multi_turn_rl_trainer import MultiTurnRLTrainer
 
         attached_job = MultiTurnRLTrainer.attach(
-            "mock-oss-test-mtrl-20260616153024", session=boto3.Session(region_name=_REGION)
+            "mock-oss-test-mtrl-20260910094327", session=boto3.Session(region_name=_REGION)
         )
 
         evaluator = MultiTurnRLEvaluator(

sagemaker-train/tests/integ/train/test_mtrl_trainer_integration.py

@@ -54,7 +54,7 @@ def _get_account_id():
     "729646638167": {
         "env_name": "PROD",
         #"existing_job_name": "mock-oss-test-mtrl-20260611170946",
-        "existing_job_name": "mock-oss-test-mtrl-20260806120845",
+        "existing_job_name": "mock-oss-test-mtrl-20260910094327",
         "base_model": "mock-oss-test",
         "agent_core_arn": "arn:aws:bedrock-agentcore:us-west-2:729646638167:runtime/sagemaker_rft_prod_gsm8k_streaming-Yk6O377mUS",
         "dataset": "s3://sagemaker-rft-729646638167/prompts/gsm8k_small/prompts.parquet",