impl(o11y): introduce error attributes

[diegomarquezp]

Ports the error.type and status.message telemetry features from sdk-platform-java.

[gemini-code-assist]

Summary of Changes

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This pull request significantly refines the tracing telemetry by introducing dedicated attributes for error types, exception types, and status messages. These additions provide a more detailed and standardized way to categorize and understand failures occurring within client-side operations, improving observability and debugging capabilities. The changes ensure that critical error information is consistently captured in OpenTelemetry spans, offering clearer insights into the root causes of issues.

Highlights

• Enhanced Error Telemetry: Introduced new OpenTelemetry attributes (error.type, status.message, exception.type) to provide more granular details on client-side errors within tracing spans.
• Standardized Error Type Extraction: Added a new utility class ErrorTypeUtil to consistently extract low-cardinality error types from Throwable objects, prioritizing google.rpc.ErrorInfo.reason, client-side network/operational errors, specific server codes, and language-specific exception names.
• Span Attribute Population: Modified SpanTracer to automatically populate the new error telemetry attributes on attempt spans when operations fail, including a recursive search for the most relevant error message.
• API Tracer Update: Extended the ApiTracer interface with a new default method requestSent(long requestSize) to allow for tracking the size of streaming requests.
• Comprehensive Testing: Added extensive unit and integration tests to validate the correct extraction and recording of error types and messages across various client-side and server-side failure scenarios for both gRPC and HTTP/JSON transports.

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[gemini-code-assist]

Code Review

This pull request introduces a new ErrorTypeUtil class to provide a standardized way of classifying exceptions into specific error types (e.g., client timeout, connection error, authentication error) for OpenTelemetry tracing. It adds new observability attributes (error.type, exception.type, status.message) and integrates this error classification into the SpanTracer to enrich span data upon failed attempts. The changes also include comprehensive unit and integration tests to validate the new error type extraction and tracing functionality. Feedback from the review includes correcting incorrect copyright years, removing redundant semicolons and toString() overrides, and updating Javadoc for accuracy.