kea: T7821: Use correct Kea unit files

Author: sarthurdev

data/live-build-config/hooks/live/18-enable-disable_services.chroot

@@ -5,9 +5,9 @@ systemctl disable syslog.service
 systemctl disable rsyslog.service
 systemctl disable arpwatch.service
 systemctl disable smartd.service
-systemctl disable kea-dhcp4.service
-systemctl disable kea-dhcp6.service
-systemctl disable kea-dhcp-ddns.service
+systemctl disable isc-kea-dhcp4-server.service
+systemctl disable isc-kea-dhcp6-server.service
+systemctl disable isc-kea-dhcp-ddns-server.service
 systemctl disable isc-dhcp-relay.service
 systemctl disable nfacctd.service
 systemctl disable sfacctd.service