chore(bigquery-jdbc): link OpenTelemetry instrumentation with underlying SDK

[keshavdandeva]

b/517588332

This PR completes the linkage between the JDBC driver's OpenTelemetry instrumentation and the underlying BigQuery SDK to ensure full end-to-end traces.

Key Changes

• Dependency: Added io.grpc:grpc-opentelemetry to intercept low-level gRPC network spans for the Storage API.
• REST API: Enabled setEnableOpenTelemetryTracing(true) in BigQueryOptions to unlock SDK-level tracing for standard queries.
• HTAPI (Storage API): Enabled setEnableOpenTelemetryTracing(true) in BigQueryReadSettings and wired the GrpcOpenTelemetry interceptor to the channel builder.
• Global OTel: Ensured the useGlobalOpenTelemetry flag is respected when configuring the Storage API client.

[gemini-code-assist]

Code Review

This pull request configures OpenTelemetry tracing for BigQuery and BigQueryRead connections, introduces a ReentrantLock to safely attach the global log handler, and ensures logging levels are restored in tests. The review feedback identifies a compilation error in BigQueryConnection.java where ManagedChannelBuilder needs to be cast to its raw type to satisfy generic bounds, and suggests unconditionally restoring the logger level in BigQueryJdbcLoggingBaseTest.java to prevent test pollution.

[keshavdandeva]

/gemini review

[gemini-code-assist]

Code Review

This pull request integrates OpenTelemetry tracing into the BigQuery JDBC connection by adding the grpc-opentelemetry dependency and configuring the gRPC channel provider with GrpcOpenTelemetry when telemetry is enabled. It also explicitly enables OpenTelemetry tracing in both BigQueryOptions and BigQueryReadSettings. The review feedback suggests simplifying a lambda expression used in the channel configurator to make the code more concise and idiomatic.