Enable timeout setting for Python TestPipeline (#29646)

[Naseer-010]

This PR introduces a timeout setting for TestPipeline in Apache Beam’s Python SDK.

---

Changes:

• Adds a timeout parameter to TestPipeline to limit execution time.
• Ensures test runs terminate if they exceed the specified timeout.
• Updates relevant test cases to validate the timeout behavior.
  Fixes:
• Closes [Task]: Enable to set timeout for Python TestPipeline #29646.

[github-actions]

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[Naseer-010]

Hey @mentors this is my first pr and contribution too
Can you please take time to explain me why are these tests are failing? I am ready to learn and tackle new challenges

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R: @tvalentyn for label python.

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[tvalentyn]

Thanks for you contribution!

Left some comments.

PTAL at lint errors - you can find test failure logs by clicking on 'Details'. There is:

Running pylint...
************* Module apache_beam.testing.test_pipeline
apache_beam/testing/test_pipeline.py:100:0: C0301: Line too long (91/80) (line-too-long)

[Naseer-010]

@tvalentyn 4 of the tests are failing and can i raise a issue for this ? If yes what is the format?
The main reason why these are failing is what I figured out is because of unmatched python versions and what the error is showing is py39 not found, py38 not found...
how can so many versions be installed in one machine?

[tvalentyn]

Let's focus on failures that can be attributed to this PR for now, we can re-run the unrelated test suites, they might be flakes or something that has been already fixed. The Lint and Formatter errors are caused by the changes in this PR though.