Pass attributes from ClientGraphQlRequest to WebClient request

[holzerch]

Attributes set to the ClientGraphQlRequest are not forwarded/set on the WebClient when making a POST request within HttpGraphQlTransport.

I actually wanted to set the CLIENT_REGISTRATION_ID on a request basis in oder to use different Spring Security based ClientRegistrations per request. However the attribute is never forwarded to the WebClient and therefor not accessible from the Spring Security filter function.

[rstoyanchev]

Yes, we can extend the reach of ClientGraphQlRequest attributes for transports that support passing attributes. Logically it's the same request.