Fix: Model::getValidationRules() return when using shared rules
Fix: Model::getValidationRules() return when using shared rules

This should fix https://github.com/codeigniter4/CodeIgniter4/issues/3039 .
natanfelles/CodeIgniter4,samsonasik/CodeIgniter4,samsonasik/CodeIgniter4,natanfelles/CodeIgniter4,ytetsuro/CodeIgniter4,lonnieezell/CodeIgniter4,natanfelles/CodeIgniter4,ytetsuro/CodeIgniter4,ytetsuro/CodeIgniter4,lonnieezell/CodeIgniter4,bcit-ci/CodeIgniter4,natanfelles/CodeIgniter4,natanfelles/CodeIgniter4,gustavojm/CodeIgniter4,lonnieezell/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,lonnieezell/CodeIgniter4,bcit-ci/CodeIgniter4,samsonasik/CodeIgniter4,ytetsuro/CodeIgniter4,ytetsuro/CodeIgniter4,samsonasik/CodeIgniter4,kenjis/CodeIgniter4,lonnieezell/CodeIgniter4,gustavojm/CodeIgniter4,ytetsuro/CodeIgniter4,natanfelles/CodeIgniter4,samsonasik/CodeIgniter4,gustavojm/CodeIgniter4,gustavojm/CodeIgniter4,kenjis/CodeIgniter4,lonnieezell/CodeIgniter4,bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4