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.

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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 failing? I am ready to learn and tackle new challenges

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