Openshift/router: openshift/router: mtls client certificate spoofing via unstripped x-ssl-client headers on http frontend

A flaw was found in the OpenShift Router. When a Route has `insecureEdgeTerminationPolicy` set to Allow, the HTTP frontend does not remove `X-SSL-Client-*` headers from incoming requests. This allows an unauthenticated attacker to send plain HTTP requests with crafted `X-SSL-Client-*` headers. As a result, backends relying on these headers for mutual TLS (Transport Layer Security) authentication can be bypassed, enabling the attacker to impersonate client certificate identities.