fix: ModelTrainer generates sm_train.sh with CRLF line endings on Windows causing tra (5904)

[sagemaker-bot]

Description

AI-generated fix.

Related Issue

Related issue: 5904

Changes Made

• sagemaker-train/src/sagemaker/train/model_trainer.py
• sagemaker-train/tests/unit/train/test_model_trainer.py

AI-Generated PR

This PR was automatically generated by the PySDK Issue Agent.

• Confidence score: 95%
• Classification: bug
• SDK version target: V3

Merge Checklist

• Changes are backward compatible
• Commit message follows prefix: description format
• Unit tests added/updated
• Integration tests added (if applicable)
• Documentation updated (if applicable)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.98%. Comparing base (e6905ed) to head (2759dce).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5907   +/-   ##
=======================================
  Coverage   89.97%   89.98%           
=======================================
  Files         286      286           
  Lines       39217    39235   +18     
=======================================
+ Hits        35286    35305   +19     
+ Misses       3931     3930    -1     

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