Fix mismatched log field types more

[masaori335]

Following #13223. Four more LogFields are initialized with unmatched types with marshal/unmarshal function.

Seems we're easily make mistake with this, we need something to check it at compile time.

[Copilot]

Pull request overview

This PR continues the logging field type cleanup from #13223 by correcting additional LogField type declarations in Log::init_fields() so they match the actual marshal/unmarshal behavior, improving correctness for type-driven consumers (e.g., filters/aggregates and binary log readers).

Changes:

• Re-type client_ssl_cert_provided (cscert) and proxy_ssl_cert_provided (pscert) from STRING to sINT to match marshal_*_provided_cert() writing a single int.
• Re-type next_hop_port (nhp) from IP to sINT to match marshal_next_hop_port() writing the port as an int.
• Re-type proxy_protocol_authority (ppa) from IP to STRING to match marshal_proxy_protocol_authority() writing a string payload.