OTEL tracing updates

[mmcshane]

What changed?

• Adds Cassanra CQL tracing
• Take TracerProvider.Tracer lookup off of the critical path in gRPC handling
• Ignore errors when shutting down TracerProvider
• Use noop TracerProvider if no exporters are configured

Why? Would like to see Cassandra queries in traces

How did you test it? Existing unit tests (no behavior change)

Potential risks Adds overhead on query execution path - need to watch latency metrics

Is hotfix candidate?