Add LangSmith tracing sample #1144

Job	Run time
build-lint-test (3.10, macos-arm)	6m 15s
build-lint-test (3.14, windows-latest)	18m 0s
build-lint-test (3.14, macos-intel)	22m 10s
build-lint-test (3.10, ubuntu-latest)	5m 48s
build-lint-test (3.14, ubuntu-latest)	14m 53s
build-lint-test (3.14, macos-arm)	10m 26s
build-lint-test (3.10, macos-intel)	7m 36s
build-lint-test (3.10, windows-latest)	6m 38s
	1h 31m 46s

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