fix(nextcloud): use service module in handlers for init-system portability

systemd module fails in containers/chroots without systemd;
service module works with sysvinit scripts and systemd alike.
Verified by sandbox run: ok=15 changed=9 failed=0, idempotent.

roles/homelab/nextcloud/handlers/main.yml

@@ -1,11 +1,11 @@
 ---
 
 - name: "restart nftables"
-  ansible.builtin.systemd:
+  ansible.builtin.service:
     name: nftables
     state: restarted
 
 - name: "restart apache2"
-  ansible.builtin.systemd:
+  ansible.builtin.service:
     name: apache2
     state: restarted