fix(user): ignore ssh key errors in check mode

In check mode, the task fails if it's supposed to be adding ssh keys to
a user who doesn't exist. Ignoring errors in check mode makes it
possible to run the task in check mode even if there are new users to be
added.

roles/user/tasks/user.yml

@@ -25,3 +25,4 @@
     exclusive: true
   become: true
   when: "user.attrs.active | default(false)"
+  ignore_errors: "{{ ansible_check_mode }}"