spanner: unsupported sampler error occurs while keeping the session alive

## Client

go-spanner

## Environment

GKE

## Go Environment

$ go version
1.22.9

Using https://pkg.go.dev/cloud.google.com/go/spanner v1.73.0

## Code and Dependencies
go library for Spanner suggests that there is no need to handle session on our own and we are not doing any of the thing on our own. It's the HealthCheckWorker which is doing all of the things on it's own.

### Why is this error occurring?
L299 `octrace.WithSampler(octrace.NeverSample())` specifies the sampler.
See: https://github.com/googleapis/google-cloud-go/blob/main/spanner/session.go#L299-L300

However, if you check the opentelemetry-go implementation, it returns an error if sampler is not nil.
See: https://github.com/open-telemetry/opentelemetry-go/blob/main/bridge/opencensus/internal/oc2otel/tracer_start_options.go#L32

Why is it calling `StartSpan` even though it is not sampling?
Also, only this code uses OpenCensus to run `StartSpan`.

How about erasing the L299 to L300 code based on the following two points
- It is not actually sampling.
- `StartSpan` with OpenCeusus is deprecated. See: https://github.com/googleapis/google-cloud-go/blob/main/internal/trace/trace.go#L38

If you have other ideas, I would appreciate your input.

## Expected behavior

There should not be any error while executing Select 1 .

## Actual behavior

Getting Below error
starting span "cloud.google.com/go/spanner.ping": unsupported sampler: 0x158af20

## Additional context

A similar [Issue](https://github.com/googleapis/google-cloud-go/issues/7100) has been created previously, but the problem still persists.