Incorrect port in the location header for redirects

[kate-osborn]

The port in the location header for an HTTPRoute with a requestRedirect filter must be set based on the rules in the spec: https://gateway-api.sigs.k8s.io/v1alpha2/references/spec/#gateway.networking.k8s.io%2fv1beta1.HTTPRequestRedirectFilter

The conformance tests HTTPRouteRedirectScheme and HTTPRouteRedirectPortAndScheme are failing with errors like the following:
for https scheme, expected redirected port to be 443 or not set, got "80"

or:

for http scheme, expected redirected port to be 80 or not set, got "443"

Acceptance Criteria:

• Set the port in the location header of a redirect based on the rules in the spec
• Make sure the conformance tests mentioned above pass