nftables(role): reload instead of restart

This should make the role more robust against misconfigurations.

roles/nftables/handlers/main.yaml

@@ -1,5 +1,5 @@
-- name: Restart nftables service
+- name: Reload nftables service
   ansible.builtin.systemd_service:
     name: nftables
-    state: restarted
+    state: reloaded
   become: true

roles/nftables/tasks/main.yaml

@@ -12,4 +12,4 @@
     owner: root
     group: root
   become: true
-  notify: Restart nftables service
+  notify: Reload nftables service