ci: mark some unreliable tests (#9382)

Marking recently-failed tests


https://app.circleci.com/pipelines/github/DataDog/dd-trace-py/62400/workflows/eddd6d71-2921-41de-8b17-4a43d22ce511/jobs/3891138

https://app.circleci.com/pipelines/github/DataDog/dd-trace-py/62385/workflows/19270a5d-be1d-4007-bdcb-8711682e4e6d/jobs/3890437

## Checklist

- [x] Change(s) are motivated and described in the PR description
- [x] Testing strategy is described if automated tests are not included
in the PR
- [x] Risks are described (performance impact, potential for breakage,
maintainability)
- [x] Change is maintainable (easy to change, telemetry, documentation)
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed or label `changelog/no-changelog` is set
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/))
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))
- [x] If this PR changes the public interface, I've notified
`@DataDog/apm-tees`.

Author: emmettbutler

tests/contrib/langchain/test_langchain_community.py

@@ -151,6 +151,7 @@ def test_ai21_llm_sync(langchain, langchain_community, request_vcr):
         llm.invoke("Why does everyone in Bikini Bottom hate Plankton?")
 
 
+@flaky(1735812000)
 def test_openai_llm_metrics(langchain, langchain_openai, request_vcr, mock_metrics, mock_logs, snapshot_tracer):
     llm = langchain_openai.OpenAI()
     with request_vcr.use_cassette("openai_completion_sync.yaml"):
@@ -530,6 +531,7 @@ def test_cohere_math_chain_sync(langchain, langchain_community, request_vcr):
         chain.invoke("what is thirteen raised to the .3432 power?")
 
 
+@flaky(1735812000)
 @pytest.mark.snapshot
 def test_openai_sequential_chain(langchain, langchain_openai, request_vcr):
     """

tests/debugging/test_debugger.py

@@ -1143,6 +1143,7 @@ def test_debugger_continue_wrapping_after_first_failure():
         assert d._probe_registry[probe_ok.probe_id].installed
 
 
+@flaky(1735812000)
 def test_debugger_redacted_identifiers():
     import tests.submod.stuff as stuff