Streaming response is converted to text and sent all at once using tsed-serverless-http
### Describe the bug

I'm using **TSED v8.5.1** with **tsed-serverless-http** and encountering an issue where a streaming response (`Readable`) is being converted to text and sent as a single response instead of being streamed incrementally. I'm unsure if this is a limitation of `tsed-serverless-http`, a misconfiguration on my part, or a bug.


### **Issue**
- The expected behavior is for the response to be streamed to the client as chunks.  
- However, what happens instead is that the entire response is buffered and sent at once as text.  

### **Actual Behavior**
- The response is buffered and sent as a single text response after completion.

### **Question**
- Is this the expected behavior of `tsed-serverless-http`?
- Is there a configuration setting that enables proper streaming?
- If this is a bug, is there a known workaround?

Thank you for your support! Please let me know if further details or logs are required.



### To Reproduce

1. Deploy a serverless function using `tsed-serverless-http` and `PlatformExpress`.
2. Implement a route that returns a `Readable` stream.
3. Observe that the client receives the response only after the entire stream completes, rather than progressively.

### Expected behavior

- The client should receive the response in chunks as they are streamed.


### Code snippets

```TypeScript

@Controller("/:id")
export class GenerateContentController {
  constructor(
    private contentGeneratorService: ContentGeneratorService,
  ) {}

  @Post("/generate-content")
  @(Returns(200, String).Binary())
  async post(
    @PathParams("id") id: string,
  ): Promise<any> {
    const result = await this.contentGeneratorService.getContent(id);
    return result.stream; // Readable
  }
}


// Lambda Setup

const platform = PlatformServerlessHttp.bootstrap(Server, {
  adapter: PlatformExpress
});

export const handler = platform.handler();
```

### Repository URL example

_No response_

### OS

amazon linux

### Node version

v20

### Library version

v8.5.1

### Additional context

_No response_