Override log levels after log handler is created

[Abacn]

Follow up of #18222

• This fixes error message about log level overrides not shown when
  executed with Dataflow runner

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[codecov]

Codecov Report

Merging #22191 (5ad1e9b) into master (ec47b12) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #22191      +/-   ##
==========================================
+ Coverage   74.21%   74.24%   +0.02%     
==========================================
  Files         702      702              
  Lines       92829    92962     +133     
==========================================
+ Hits        68892    69018     +126     
- Misses      22670    22677       +7     
  Partials     1267     1267              

Flag	Coverage Δ
python	83.62% <100.00%> (+0.02%)	⬆️

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

Impacted Files	Coverage Δ
...thon/apache_beam/runners/worker/sdk_worker_main.py	78.48% <100.00%> (+0.12%)	⬆️
.../python/apache_beam/testing/test_stream_service.py	88.09% <0.00%> (-4.77%)	⬇️
.../apache_beam/runners/interactive/dataproc/types.py	93.10% <0.00%> (-3.45%)	⬇️
sdks/python/apache_beam/utils/interactive_utils.py	95.12% <0.00%> (-2.44%)	⬇️
.../python/apache_beam/transforms/periodicsequence.py	98.38% <0.00%> (-1.62%)	⬇️
...che_beam/runners/interactive/interactive_runner.py	90.06% <0.00%> (-1.33%)	⬇️
...ache_beam/runners/dataflow/ptransform_overrides.py	90.12% <0.00%> (-0.62%)	⬇️
sdks/python/apache_beam/typehints/schemas.py	94.32% <0.00%> (-0.34%)	⬇️
...dks/python/apache_beam/options/pipeline_options.py	94.76% <0.00%> (-0.21%)	⬇️
...hon/apache_beam/runners/worker/bundle_processor.py	93.54% <0.00%> (-0.13%)	⬇️
... and 13 more

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[Abacn]

Tested on dataflow runner v2. Invalid log overrides option now has the following log message (at the very beginning of worker log):

2022-07-07T20:13:44.765811204ZUnable to parse sdk_harness_log_level_overrides ['{"apache_beam.io.fileio":WARN}']. Log level overrides won't take effect.

Using a valid option (e.g. --sdk_harness_log_level_overrides={\"apache_beam.io.fileio\":\"WARN\"}), log level settings take effect as expected.

R: @tvalentyn

[github-actions]

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

[Abacn]

R: @TheNeuralBit

[TheNeuralBit]

Would it be possible to add a test that fails without this change?

[Abacn]

retest this please

[Abacn]

Would it be possible to add a test that fails without this change?

Addressed. please take another look, thanks!