ci: mark unreliable langchain_community tests

[emmettbutler]

This change marks some unreliable tests in the langchain_community suite. Some of these had been recently unmarked in ecc56cf, but it seems like they still have some underlying unreliability (example).

Checklist

• Change(s) are motivated and described in the PR description
• Testing strategy is described if automated tests are not included in the PR
• Risks are described (performance impact, potential for breakage, maintainability)
• Change is maintainable (easy to change, telemetry, documentation)
• Library release note guidelines are followed or label changelog/no-changelog is set
• Documentation is included (in-code, generated user docs, public corp docs)
• Backport labels are set (if applicable)
• If this PR changes the public interface, I've notified @DataDog/apm-tees.

Reviewer Checklist

• Title is accurate
• All changes are related to the pull request's stated goal
• Description motivates each change
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Change is maintainable (easy to change, telemetry, documentation)
• Release note makes sense to a user of the library
• Author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: emmett.butler/flaky-langchain
Commit report: 96a67f4
Test service: dd-trace-py

✅ 0 Failed, 310 Passed, 140 Skipped, 8m 16.7s Total duration (2m 12.28s time saved)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 10.29%. Comparing base (3bc3051) to head (b60ff60).

Files	Patch %	Lines
...ests/contrib/langchain/test_langchain_community.py	0.00%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #9490       +/-   ##
===========================================
- Coverage   69.41%   10.29%   -59.13%     
===========================================
  Files        1315     1285       -30     
  Lines      124706   122866     -1840     
===========================================
- Hits        86567    12645    -73922     
- Misses      38139   110221    +72082     

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[Yun-Kim]

I've done some investigating and it looks like the underlying issue is a version issue with vcrpy (reading cassette files). I'm good to mark these tests as flaky for now, but will be pinning vcrpy in a future PR which should hopefully remove the flakiness.

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-06-10 15:33:32

Comparing candidate commit 96a67f4 in PR branch emmett.butler/flaky-langchain with baseline commit 20e87ca in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 96 metrics, 0 unstable metrics.