improve knot roles reloading behavior

With this change, the nameserver is not restarted on configuration
updates but only reloaded instead.

roles/knot/handlers/main.yaml

@@ -1,16 +1,10 @@
 ---
-- name: restart knot
+- name: reload knot
   tags: [ auth-dns ]
   become: true
   ansible.builtin.systemd:
     name: knot.service
-    state: restarted
-
-- name: reload knot zones
-  tags: [ auth-dns ]
-  become: true
-  changed_when: true
-  ansible.builtin.command: "knotc zone-reload"
+    state: reloaded
 
 - name: netplan apply
   tags: [ auth-dns ]