Unable to use Google Well Known Types with @grpc/reflection and @grpc/proto-loader

### Problem description
When using @grpc/proto-loader to load a .proto file that imports Google Well-Known Types (for example, google/protobuf/struct.proto), the server reflection fails to recognize those types at runtime.

Although proto-loader correctly builds and adds the Google WKTs to the packageDefinition object, running grpcurl with service reflection enabled produces the following error:

cannot resolve type: "*.google.protobuf.Duration" not found
A similar issue has been discussed here: https://github.com/fullstorydev/grpcurl/issues/459

### Reproduction Steps

Proto:

```
syntax = "proto3";

package multiply_function;

import "google/protobuf/duration.proto";

message Request {
int32 op1 = 1;
int32 op2 = 2;
}

message Response {
int32 prod = 1;
google.protobuf.Duration processing_time = 3; // How long the calculation took
}

service Multiply {
rpc multiply (Request) returns (Response);
}
```

```
// Load a .proto file that imports a Google well-known type
const packageDefinition = await load(protoFile);

// Create and register the ReflectionService
const reflectionService = new ReflectionService(packageDefinition);
reflectionService.addToServer(grpcServer);

```
### Environment
Node.js: v22.14.0

Dependencies:
@grpc/grpc-js: 1.13.3
@grpc/proto-loader: 0.7.15
@grpc/reflection: 1.0.4

### Additional context

I’ve also tried supplying complete file descriptors—including the Google WKTs, but the issue persists. Any help would be greatly appreciated!