ARROW-17296: [Python] Update serialized metadata size in pyarrow.parquet.read_metadata doctest - #13790

https://issues.apache.org/jira/browse/ARROW-17296

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+1. The CI failure is unrelated

Benchmark runs are scheduled for baseline = db6c099 and contender = ee874d6. ee874d6 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Failed ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️0.78% ⬆️0.0%] test-mac-arm
[Finished ⬇️0.82% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.07% ⬆️0.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Failed] ee874d67 ec2-t3-xlarge-us-east-2
[Finished] ee874d67 test-mac-arm
[Finished] ee874d67 ursa-i9-9960x
[Finished] ee874d67 ursa-thinkcentre-m75q
[Failed] db6c099b ec2-t3-xlarge-us-east-2
[Failed] db6c099b test-mac-arm
[Finished] db6c099b ursa-i9-9960x
[Finished] db6c099b ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

['Python', 'R'] benchmarks have high level of regressions.
test-mac-arm