Reject requests with missing/invalid client IP once confirmed no legitimate traffic relies on them

[jkrvivian]

In get_client_ip_addr (crates/iota-core/src/authority_server.rs), two ClientIpStatus branches currently only log + increment a metric and return None instead of rejecting the request:

• SocketAddrMissing — IO type doesn't implement Connected, or a unix domain socket is used.
• XForwardedForInvalidUtf8 — invalid UTF-8 in the x-forwarded-for header.

Once we have confirmed via the connection_ip_not_found and forwarded_header_invalid metrics that no legitimate traffic hits these cases, reject such requests rather than letting them through with no client IP.