MiddlewareServer only invokes the last middleware, but never propagates the request to the previous ones

MiddlewareServer only invokes the last middleware, but never propagates the request to the previous ones.

https://github.com/apple/swift-http-api-proposal/blob/d7527be34e41fcae2938cdbdd40368e77a22a5fa/Examples/MiddlewareServer/MiddlewareServer.swift#L35

```swift
try await ExampleMiddlewareServer(
server: server
) { server in
server
.logging(logger: Logger(label: "Logger"))
.requestHandler()
}.serve()
```

The `.logging(...)` middleware is never invoked.

Open Examples/MiddlewareServer/MiddlewareServer.swift at the linked line and trace how the chained logging and requestHandler middleware are invoked. Reproduce the example request and verify that the logging middleware runs before the request handler; the issue is done when the request propagates through both middleware components.

Written by the indexing model from the issue text.