Prevent playbook abort if variables are not defined

- Skip task `Deploy sudo configurations` when `sudo_permissions` is not defined
- Skip task `Deploy polkit configurations` when `polkit_rules` is not defined

roles/lmn_security/tasks/main.yml

@@ -39,6 +39,7 @@
       {% for user, programs in sudo_permissions.items() %}
       {{ user }} ALL=(root) NOPASSWD: {% for program in programs %}{{ program }}{% if not loop.last %}, {% endif %}{% endfor %}
       {% endfor %}
+  when: sudo_permissions is defined
 
 - name: Deploy polkit configurations
   ansible.builtin.template:
@@ -46,3 +47,4 @@
     dest: /etc/polkit-1/rules.d/lmn-security.rules
     mode: '0644'
   notify: Restart polkit
+  when: polkit_rules is defined