Revert "Force discarding mode in with_fanout without rewindowing."

[tvalentyn]

Reverts #23828

Reason: caused a memory increase for one of internal customers. Reverting while the investigation is happening.

Original issue: #20528

[tvalentyn]

R: @robertwb @kerrydc

[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control

[codecov]

Codecov Report

Merging #24378 (2897e1a) into master (1115154) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #24378      +/-   ##
==========================================
- Coverage   73.36%   73.35%   -0.02%     
==========================================
  Files         718      718              
  Lines       97034    97033       -1     
==========================================
- Hits        71193    71180      -13     
- Misses      24511    24523      +12     
  Partials     1330     1330              

Flag	Coverage Δ
python	82.99% <ø> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sdks/python/apache_beam/transforms/core.py	92.90% <ø> (+0.36%)	⬆️
.../python/apache_beam/testing/test_stream_service.py	88.09% <0.00%> (-4.77%)	⬇️
sdks/python/apache_beam/utils/interactive_utils.py	95.12% <0.00%> (-2.44%)	⬇️
...che_beam/runners/interactive/interactive_runner.py	90.50% <0.00%> (-1.27%)	⬇️
sdks/python/apache_beam/io/localfilesystem.py	90.97% <0.00%> (-0.76%)	⬇️
sdks/python/apache_beam/runners/direct/executor.py	96.46% <0.00%> (-0.55%)	⬇️
...ython/apache_beam/io/gcp/bigquery_read_internal.py	57.21% <0.00%> (-0.49%)	⬇️
...hon/apache_beam/runners/worker/bundle_processor.py	93.42% <0.00%> (-0.38%)	⬇️
...ks/python/apache_beam/runners/worker/sdk_worker.py	89.24% <0.00%> (-0.33%)	⬇️
sdks/python/apache_beam/io/gcp/bigquery.py	71.11% <0.00%> (-0.24%)	⬇️
... and 2 more

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