feat(pubsub): extract trace information

[radhus]

Pass a context that contains trace information extracted from the incoming message, allowing traces to span from publishers over to subscribers.

In order for publishers to include tracing information, the pubsub client should be created with:

client, err := pubsub.NewClientWithConfig(
        ctx,
        cloudrunner.Runtime(ctx).ProjectID,
        &pubsub.ClientConfig{
                EnableOpenTelemetryTracing: true,
        },

Depends on https://github.com/googleapis/google-cloud-go/pull/10827 which is included in v1.43.0.