/etc/apparmor/init/network-interface-security/sbin.dhclient is in isc-dhcp-client 4.1.ESV-R4-0ubuntu5.10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /etc/apparmor/init/network-interface-security/../../../apparmor.d/sbin.dhclient