borgmatic: check mode fixes

roles/borgmatic/tasks/main.yaml

@@ -12,12 +12,14 @@
 - name: Install borgmatic
   ansible.builtin.apt:
     name: borgmatic
+  register: _borgmatic_install
 
 - name: Disable borgmatic global timer
   ansible.builtin.systemd_service:
     name: borgmatic.timer
     state: stopped
     enabled: false
+  when: "not (ansible_check_mode and _borgmatic_install.changed)"
 
 - name: Add systemd drop-in service for borgmatic
   ansible.builtin.template: