Introducing OpenTelemetry support for LangSmith

LangSmith now supports ingesting traces in OpenTelemetry format, an open standard for distributed tracing and observability. This update allows developers to instrument and export telemetry data across various programming languages, frameworks, and monitoring tools for broad interoperability. With this integration, LangSmith's API layer can accept OpenTelemetry traces directly, providing a complete view of your application's performance with unified LLM monitoring and system telemetry. The update also supports the OpenLLMetry format, a semantic convention that enables out-of-the-box instrumentation for a range of LLM models, vector databases, and common LLM frameworks. LangSmith plans to support other semantic conventions as they evolve.