fix: is_cli() returns true when $_SERVER['HTTP_USER_AGENT'] is missing
fix: is_cli() returns true when $_SERVER['HTTP_USER_AGENT'] is missing

Fixes #5336

kenjis/CodeIgniter4,samsonasik/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,samsonasik/CodeIgniter4,samsonasik/CodeIgniter4,lonnieezell/CodeIgniter4,kenjis/CodeIgniter4,bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4,lonnieezell/CodeIgniter4,lonnieezell/CodeIgniter4,lonnieezell/CodeIgniter4,kenjis/CodeIgniter4,samsonasik/CodeIgniter4,lonnieezell/CodeIgniter4,kenjis/CodeIgniter4,lonnieezell/CodeIgniter4