padding to max_seq_len when packing or enable sp

[Jonathans575]

Before submitting

• Lint code. If there are lint issues, please format the code first.

# Install and register `pre-commit` in the project folder
pip install pre-commit && pre-commit install

# Process previous code files separately
pre-commit run --file XXXX.py

• Add test cases into tests folder. If there are codecov issues, please add tests cases first.

PR types

PR changes

Description

[paddle-bot]

Thanks for your contribution!

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@67bd0f6). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
paddleformers/cli/train/dpo/workflow.py	0.00%	1 Missing ⚠️
paddleformers/cli/train/sft/workflow.py	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (0.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #2749   +/-   ##
==========================================
  Coverage           ?   29.06%           
==========================================
  Files              ?      334           
  Lines              ?    55895           
  Branches           ?        0           
==========================================
  Hits               ?    16248           
  Misses             ?    39647           
  Partials           ?        0           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[lugimzzz]

LGTM