conformance suite doesn't ever try sending x-fapi-customer-ip-address

The conformance suite doesn't currently send x-fapi-customer-ip-address. It probably should, including both ipv4 and ipv6 variants.

We do seem to try sending x-fapi-auth-date, but don't ever try a request without it (it's optional to send).

TPPs have reported that some banks reject requests where x-fapi-customer-ip-address contains an IPv6 address.