Namespace not retained when generating rpc calls

Please consider the following .proto file:

```
package package.rpc.asks;
import "package/actions/asks.proto";
service Ask {
rpc GetAskSnapshot(package.actions.asks.RequestAskSnapshot) returns (package.actions.asks.AskSnapshot) { }
}
```

I would expect this to generate a Ruby file

```ruby
module Package
module Rpc
module Asks
class AskService < Twirp::Service
package 'superlist.rpc.asks'
service 'Ask'
rpc :GetAskSnapshot, Package::Actions::Asks::RequestAskSnapshot, Package::Actions::Asks::AskSnapshot, :ruby_method => :get_ask_snapshot
end
```

however, it drops the package name for the parameter and generates

```ruby
module Package
module Rpc
module Asks
class AskService < Twirp::Service
package 'superlist.rpc.asks'
service 'Ask'
rpc :GetAskSnapshot, RequestAskSnapshot, AskSnapshot, :ruby_method => :get_ask_snapshot
end
```

which results in an error when trying to import the service file. The `RequestAskSnapshot` is expected as `Package::Rpc::Asks::AskService::RequestAskSnapshot` which doesn't exists (as it's supposed to be `Package::Actions::Asks::RequestAskSnapshot`).

Am I missing something?

Start with the provided .proto definition and compare its generated Ruby service output, tracing how the fully qualified RPC request and response types are rendered. Done means the generated rpc declaration retains Package::Actions::Asks::RequestAskSnapshot and Package::Actions::Asks::AskSnapshot so the service file imports successfully.

Written by the indexing model from the issue text.