feat(gax): accept clientOptions in createApiCall for telemetry tracing

[shivanee-p]

Adds clientOptions support and telemetry gating logic to createApiCall in google-gax to support OpenTelemetry tracing.

• Defined StaticTraceContext and added enableTelemetryTracing?: boolean and internalTelemetryInfo?: StaticTraceContext to ClientOptions.
• Accepted clientOptions in createApiCall and added conditional gating checking enableTelemetryTracing, internalTelemetryInfo, and GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED.
• Updated test helpers to forward clientOptions and added unit tests for tracing enablement.

[gemini-code-assist]

Code Review

This pull request introduces telemetry tracing options to ClientOptions and integrates them into createApiCall to determine if tracing is enabled. Key feedback includes explicitly checking if the GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED environment variable equals 'true' to avoid false positives with other string values. Additionally, the console.log statements used for debugging tracing status should be removed to prevent polluting the standard output of consuming applications, and the corresponding unit tests that spy on these logs should be cleaned up.

[westarle]

I think we should consider CallSettings carefully. I would take the change to