Importing proto with dotted name

## Bug Report

### Version
tonic v0.11.0
tonic-build v0.11.0

### Platform
Darwin 23.2.0 Darwin Kernel Version 23.2.0: Wed Nov 15 21:55:06 PST 2023; root:xnu-10002.61.3~2/RELEASE_ARM64_T6020 arm64

### Description

I have the following two proto files:

`foobar.proto`
```proto
syntax = "proto3";

package foo.bar;

message Foo {}

message Bar {}
```

`example.proto`
```proto
syntax = "proto3";

package example;

import "foobar.proto";

service Example {
rpc example(foo.bar.Foo) returns (foo.bar.Bar);
}
```

and a `main.rs` file:
```rust
use tonic::{Request, Response, Status};

use pb::*;

pub mod pb {
tonic::include_proto!("example");
}

#[derive(Debug, Default)]
struct Service;

#[tonic::async_trait]
impl example_service_server::ExampleService for Service {
async fn void(&self, _request: Request) -> Result, Status> {
todo!()
}
}

fn main() {}
```

When running `cargo clippy`, the following output prints:
```
error[E0433]: failed to resolve: could not find `foo` in the crate root
--> [...]/target/debug/build/tonic_bug_mre-913b1807619270b3/out/example.rs:88:60
|
88 | request: impl tonic::IntoRequest,
| ^^^ could not find `foo` in the crate root

... many more similar error messages
```

It seems like tonic is not set up to handle packages with dotted names (i.e. `foo.bar`) in imports.
If the dotted package is 'standalone', that works. Is there anything I overlooked to make this work?