feat(o11y): introduce observability flags needed within the generator

[shivanee-p]

Adds support for the o11y feature flag to gapic-generator-typescript and updates client options interface definitions in google-gax

• Added enableTelemetryTracing flag parsing (enable_telemetry_tracing=true)
• Added enableTelemetryTracing option support to API schema and Naming options
• Added optional fields to ClientOptions interface
• Added InternalTelemetry interface definition
• Added corresponding unit tests

[gemini-code-assist]

Code Review

This pull request introduces support for an enableTelemetryTracing option across the generator, schema, and client interface packages, including adding the option to ClientOptions and introducing an InternalTelemetry interface. Feedback suggests updating the parameter parsing in the generator to support both hyphenated and snake_case parameter names for consistency with other flags, and to only set the property to true when explicitly configured.

[gemini-code-assist]

To maintain consistency with other parameter parsing methods in this class (such as readLegacyProtoLoad), we should only set the property to true if the parameter is explicitly provided as 'true'. Additionally, we should support the hyphenated parameter name enable-telemetry-tracing to match the repository's naming convention for generator flags.

  private readEnableTelemetryTracing() {
    if (this.paramMap['enable-telemetry-tracing'] === 'true' || this.paramMap['enable_telemetry_tracing'] === 'true') {
      this.enableTelemetryTracing = true;
    }
  }

[shivanee-p]

I think the way that flags are read in and manipulated from the .yaml file aren't consistent depending on what level of flag it is. Because this will end up being the name of an attribute within the extra_protoc_parameters field, it wouldn't get changed to kebab case, so it will remain with the underscores.