Default value for useipinproxyheader AKA Use Client IP in Header

Nobody has claimed this yet.

Hi,

## Info
We discovered our hosting company has it set to YES and they're claiming that's the default value. I see this as a huge security risk, when anyone can easily spoof the IP by simply changing the x-forwaded-for header. Even LightSpeed docs warn agains it in https://www.litespeedtech.com/support/wiki/doku.php/litespeed_wiki:config:show-real-ip-behind-cloudflare

In our case, we expect the PHP REMOTE_ADDR to be the "last client", in our case that's the Proxy Server, but having useipinproxyheader set to YES means anyone can pretend to be from our network and gain access to IP blocked resources.

## Questions :
What's the default value for useipinproxyheader ?
[After searching the repo](https://github.com/search?q=repo%3Alitespeedtech%2Fopenlitespeed+useipinproxyheader+&type=code), I see it's NULL, but what does that mean for a default installation ?

Start with the repository search for `useipinproxyheader` and compare its NULL value with the LightSpeed documentation linked in the issue. Done means documenting the effective default for a fresh installation and explaining whether the setting can allow spoofed client IP addresses.

Written by the indexing model from the issue text.