Generate more setter and RPC samples for Pub/Sub once the surface is more stable.

We are skipping setter sample generation for `src/pubsub/src/generated/gapic_dataplane/.sidekick.toml`. We should look at that once the surface of Pub/Sub is closer to stable. At the moment, the problem is that most types in `gapic_dataplane` are internal, and some generated setter samples reference those types that cargotest cannot see.