chore(core): Update LangChainTracer to use Pydantic v2 methods

[angus-langchain]

Description

In LangSmith 0.6.0, we update the Run and RunTree object to use pydantic v2. This PR adds support for this change by using the correct method for langsmith >= 0.6.0 pydantic >= v2. It has backwards compatibility for older sdk versions as well with deprecated methods

[codspeed-hq]

CodSpeed Performance Report

Merging #34541 will improve performance by 29.25%

_{Comparing angus/langsmith-pydantic-v2 (5a0dcbd) with master (5517ef3)}

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Summary

⚡ 10 improvements
✅ 3 untouched
⏩ 21 skipped¹

Benchmarks breakdown

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	test_import_time[HumanMessage]	312.3 ms	265.9 ms	+17.46%
⚡	WallTime	test_import_time[InMemoryVectorStore]	790.7 ms	611.8 ms	+29.25%
⚡	WallTime	test_import_time[RunnableLambda]	625.8 ms	493 ms	+26.94%
⚡	WallTime	test_import_time[Runnable]	636.1 ms	497.3 ms	+27.93%
⚡	WallTime	test_import_time[LangChainTracer]	563.9 ms	437.5 ms	+28.88%
⚡	WallTime	test_import_time[CallbackManager]	588.6 ms	461.6 ms	+27.49%
⚡	WallTime	test_import_time[BaseChatModel]	661.8 ms	525.5 ms	+25.95%
⚡	WallTime	test_import_time[tool]	666.8 ms	518.2 ms	+28.66%
⚡	WallTime	test_import_time[ChatPromptTemplate]	741.8 ms	593.9 ms	+24.92%
⚡	WallTime	test_import_time[Document]	217.7 ms	185 ms	+17.64%

Footnotes

1. 21 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩