Cant read the request body using StreamReader

- NuGet Package Version: 4.0.1
- .NET SDK Version: 6.0

Steps to Reproduce:

1. Create a post endpoint without request and without result
2. Try to read the request body using StreamReader

Here is my full code: https://github.com/negrifelipe/Payments/blob/f74c37141bdf402774b42bc183bcbad538d8c243/src/Payments.Providers.PayPal/Endpoints/NotifyEndpointAsync.cs#L38 using a normal controller solved the issue

Start with NotifyEndpointAsync.cs at the linked line 38 and reproduce the request-body read using NuGet package 4.0.1 and .NET SDK 6.0. Compare the endpoint behavior with the normal controller mentioned in the report; done means a post endpoint without a request or result can read its request body through StreamReader.

Written by the indexing model from the issue text.