IpHelper does not detect invalid IP addresses

[nibra]

Steps to reproduce the issue

use Joomla\Utilities\IpHelper;

// Prepare SERVER array
$_SERVER['REMOTE_ADDR'] = 'fake';

// Prepare IpHelper singleton
IpHelper::setAllowIpOverrides(false);
IpHelper::setIp(null);

// Retrieve IP address
echo IpHelper::getIp();

Expected result

Empty string

Actual result

fake