Ansible: Set variable in task module template

gistfile1.yml

---
# Global Users Collection
users:
  - username: user1
    state: present
    name: User 1
    keys:
      - pub-key-01
    groups: 
      - www-data
  - username: user2
    state: present
    name: User 2
    keys:
      - pub-key-02
    groups: 
      - admin    

---
# Per-Host User Memebership Collection
users_host_membership:
  - username: user1
    # override defaults in global
    groups:
      - www-data
      - admin
  - username: user2
    state: absent
   
---
# User task to setup user
user: >
  {% set host_user = users_host_membership | selectattr('username', item.username) | first %}
  {% set host_user_groups = host_user | attr('groups') %}
  {% set user_state = host_user.state if host_user.state is defined else item.state %}
  name={{ item.username }}
  state={{ user_state }}
  {% if user_state = 'absent' %}
  force=yes
  remove=yes
  {% endif %}
  groups={{ (host_user_groups | join(',')) if (host_user_groups | length) > 0 else (item.groups | join(',')) if (item.groups | length) > 0 else '' }}
when: "(users_host_membership | selectattr('username', item.username) | length) > 0"
with_items: users