tandoor: ignore nonetype secret_key

roles/tandoor/tasks/main.yml

@@ -13,7 +13,7 @@
     instance: "tandoor"
     keys:
       secret_key: "{{ tandoor.secret_key
-                   if tandoor is defined and tandoor.secret_key is defined and tandoor.secret_key | length > 0
+                   if tandoor is defined and tandoor.secret_key is defined and tandoor.secret_key is not none and tandoor.secret_key | length > 0
                    else lookup('ansible.builtin.password', '/dev/null', chars=['ascii_letters', 'digits'], length=50) }}"
     owner: "{{ user.name }}"
     group: "{{ user.name }}"