HTTP body conversion will throw an InvalidOperationException when the request have an empty body

### Description

HTTP body conversion will throw an InvalidOperationException when the request have an empty body.

* **Fixed in v1.3.2**
~~When using the ASP.NET Core integration, a response is never sent back to the client, the request will hang. (Maybe related to #2476)~~

* With the built-in HTTP type with the default ``System.Text.Json`` serializer, a response with status code 500 will be sent back to the client.

* With the built-in HTTP type with ``Newtonsoft`` as the serializer :

- Sending an empty body will throw and a response with status code 500 will be sent back to the client.
- Sending an empty body with the header ``Content-Type: application/json`` allows the conversion to proceed without any error. The AzureFunction will receive a null object.

* With the in-process model sending an empty body will create an instance of the object.

With the built-in HTTP type I have traced the origin of the issue(s) back to this line of the [DefaultFromBodyConversionFeature](https://github.com/Azure/azure-functions-dotnet-worker/blob/2ece46d8dc04b6b9135c3fd6aef816d6ea4eab8f/extensions/Worker.Extensions.Http/src/DefaultFromBodyConversionFeature.cs#L66).

### Steps to reproduce

This [repository](https://github.com/Tri125/FromBodyExceptionReproCase) has been made available to demonstrate the issue.

Debug each project one by one and send all 3 request to them :

``curl -d '{ "Name": "potato" }' -H "Content-Type: application/json" -X POST http://localhost:7021/api/Function1 -v``

``curl -H "Content-Type: application/json" -X POST http://localhost:7021/api/Function1 -v``

``curl -X POST http://localhost:7021/api/Function1 -v``

This will demonstrate the issues and the difference in behavior between them.

The latest version of the packages have been used :

```
Microsoft.Azure.Core.NewtonsoftJson v2.0.0
Microsoft.Azure.Functions.Worker v1.22.0
Microsoft.Azure.Functions.Worker.Extensions.Http v3.2.0
Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore v1.3.1
Microsoft.Azure.Functions.Worker.Sdk v1.17.2
```

Start with extensions/Worker.Extensions.Http/src/DefaultFromBodyConversionFeature.cs at the linked line, then run the three curl requests from the reproduction repository against the listed HTTP configurations. Confirm whether the empty-body conversion still throws or returns a 500 response; the issue states this was fixed in v1.3.2, so the current done criteria are not otherwise defined.

Written by the indexing model from the issue text.