fix(global_defaults): add missing ssh.enabled validation assertion

roles/global_defaults/tasks/validation.yml

@@ -206,6 +206,7 @@
       - system_cfg.features.firewall.toolkit is defined
       - system_cfg.features.firewall.toolkit in ["iptables", "nftables"]
       - system_cfg.features.firewall.enabled is defined
+      - system_cfg.features.ssh.enabled is defined
       - system_cfg.features.banner.motd is defined
       - system_cfg.features.banner.sudo is defined
       - system_cfg.luks.enabled is defined