Getting "stream is not readable" since 4.16.0

The #692 PR introduced a bug when using with express and an async middleware: the IncomingMessage/Request (stream) is marked as not readable and fails when used with body-parser (for example).

Affected version: 4.16.0
Express version: 4 (didn't test it on 5)
Body parser version: 1.20.3

For the code attached, running with 4.15.0 yields:
```
{
statusCode: 200,
body: 'Hello World!',
isBase64Encoded: false,
headers: {
'x-powered-by': 'Express',
'content-type': 'text/html; charset=utf-8',
'content-length': '12',
etag: 'W/"c-Lve95gjOVATpfV8EL5X4nxwjKHE"'
}
}
```

Running with 4.16.0 yields:

```
{
statusCode: 500,
body: '\n' +
'\n' +
'\n' +
'\n' +
'Error\n' +
'\n' +
'\n' +
'

InternalServerError: stream is not readable
    at readStream (node_modules/raw-body/index.js:185:17)
    at getRawBody ... (same as below)' +

    '\n' +

    '\n',

  isBase64Encoded: false,

  headers: {

    'x-powered-by': 'Express',

    'content-security-policy': "default-src 'none'",

    'x-content-type-options': 'nosniff',

    'content-type': 'text/html; charset=utf-8',

    'content-length': 1262

  }

}

InternalServerError: stream is not readable

    at readStream (node_modules/raw-body/index.js:185:17)

    at getRawBody (node_modules/raw-body/index.js:116:12)

    at read (node_modules/body-parser/lib/read.js:79:3)

    at jsonParser (node_modules/body-parser/lib/types/json.js:138:5)

    at Layer.handle [as handle_request] (node_modules/express/lib/router/layer.js:95:5)

    at trim_prefix (node_modules/express/lib/router/index.js:328:13)

    at node_modules/express/lib/router/index.js:286:9

    at Function.process_params (node_modules/express/lib/router/index.js:346:12)

    at next (node_modules/express/lib/router/index.js:280:10)

    at src/example.ts:10:3

```


Code to reproduce:

```typescript

import serverlessExpress from '@codegenie/serverless-express';

import express from 'express';

import bodyParser from 'body-parser';

import { promisify } from 'node:util';

const app = express();

app.use(async (req, res, next) => {

  // Remove this line to "remove the problem"

  await promisify(setTimeout)(1000);

  next();

});

app.use(bodyParser.json());

app.use((req, res) => {

  res.send('Hello World!');

});

const serverlessExpressInstance = serverlessExpress({ app });

export async function handler(event: any, context: any, callback: any) {

  return serverlessExpressInstance(event, context, callback);

}

handler(

  {

    version: '2.0',

    rawPath: '/path/to/resource',

    headers: {

      "Content-Type": "application/json",

      "Content-Length": "2",

    },

    requestContext: {

      http: {

        method: 'POST',

        path: '/path/to/resource',

        protocol: 'HTTP/1.1',

        sourceIp: '192.168.0.1/32',

        userAgent: 'agent',

      },

    },

    body: "{}",

    isBase64Encoded: false,

  },

  {} as any,

  () => {},

)

  .then(console.log.bind(console))

  .catch(console.error.bind(console));

```

I believe [this](https://github.com/CodeGenieApp/serverless-express/blob/5944638c128e82ea41915fc724e72cb8b3189bbd/src/transport.js#L163) is the culprit. Express doesn't return a promise from the handle function, so if there's a middleware that starts an async operation the function will return and the stream will be marked as not readable.

```typescript

  await framework.sendRequest({ app, request, response })

  markHttpRequestAsCompleted(request) // <-- maybe this should be moved down to after the the stream completes?

  await waitForStreamComplete(response)

```

Small note, initially I had trouble finding this because I thought we were actually using vendia's serverless-express version. After fiddling with it for a couple of hours I realized it was actually "exporting" codegenie's version. So leaving this note here, in case someone else thinks they're using vendia's.