Default to Runner v2 for Python Streaming jobs.

[robertwb]

This will take effect from release 2.32 on.

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Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

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ValidatesRunner compliance status (on master branch)

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---			---		---
Java
Python	---			---		---
XLang				---		---

Examples testing status on various runners

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---	---	---	---	---	---	---
Java	---		---	---	---	---	---
Python	---	---	---	---	---	---	---
XLang	---	---	---	---	---	---	---

Post-Commit SDK/Transform Integration Tests Status (on master branch)

Go	Java	Python

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website	Whitespace	Typescript
Non-portable
Portable	---			---	---	---

See .test-infra/jenkins/README for trigger phrase, status and link of all Jenkins jobs.

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI.

[robertwb]

R: @angoenka

[codecov]

Codecov Report

Merging #15140 (5cd652e) into master (b401d23) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head 5cd652e differs from pull request most recent head d8e4ec7. Consider uploading reports for the commit d8e4ec7 to get more accurate results

@@            Coverage Diff             @@
##           master   #15140      +/-   ##
==========================================
- Coverage   83.81%   83.79%   -0.02%     
==========================================
  Files         441      441              
  Lines       59500    59505       +5     
==========================================
- Hits        49869    49865       -4     
- Misses       9631     9640       +9     

Impacted Files	Coverage Δ
...on/apache_beam/runners/dataflow/dataflow_runner.py	82.67% <100.00%> (+0.39%)	⬆️
sdks/python/apache_beam/utils/interactive_utils.py	92.68% <0.00%> (-2.44%)	⬇️
...hon/apache_beam/runners/direct/test_stream_impl.py	94.02% <0.00%> (-2.24%)	⬇️
...pache_beam/runners/interactive/interactive_beam.py	74.72% <0.00%> (-1.10%)	⬇️
...runners/interactive/display/pcoll_visualization.py	85.18% <0.00%> (-0.53%)	⬇️
...hon/apache_beam/runners/worker/bundle_processor.py	93.48% <0.00%> (-0.38%)	⬇️
...ks/python/apache_beam/runners/worker/sdk_worker.py	88.85% <0.00%> (-0.16%)	⬇️

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