Unable to follow HTTP/2 redirects

Qt6 is unable to follow HTTP2 redirects when the `Location` exposes a relative URL.

STR:

1. An HTTP/2 server with the following endpoints:
   1. /a - GET method - redirecting 301 to https://another.domain/b
   2. /b - GET method - redirecting 301 to /c
   3. /c - GET method - "hello world"
2. QNetworkRequest should follow the redirect chain and fetch "Hello world" from the final URL (https://another.domain/c) , using `QNetworkRequest::NoLessSafeRedirectPolicy` as redirect policy.

Actual result: the app returns an "HostNotFoundError" error. It seems that QT6 tries to fetch an invalid QUrl(/c) without host/scheme. Qt5 works as expected.

In attach, an HTTP2 server app written in node and a simple C++/Qt6 app.

To run the server, follow these steps:

1. generate a certificate: `openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout server.key -out server.crt`
2. Install `express`, `http2`, `http2-express-bridge` npm modules
3. node index.js