##### SUMMARY
When specifying only action name and state "absent", that fails with "missing required arguments: event_source".
Zabbix action names are unique across types (event sources), thus the event source parameter in this case is not mandated by the Zabbix API.
It would be great to either lift this limitation, or add an example in the documentation explaining why it's there.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
zabbix_action

##### ANSIBLE VERSION
latest

##### CONFIGURATION
Not relevant.

##### OS / ENVIRONMENT
Not relevant.

##### STEPS TO REPRODUCE

```yaml
  - name: "Report problems to Zabbix administrators"
    state: absent
```

##### EXPECTED RESULTS
Either success, or documented special limitation.

##### ACTUAL RESULTS
```
failed: [host] (item={u'state': u'absent', u'name': u'Report problems to Zabbix administrators'}) => {"ansible_loop_var": "item", "changed": false, "item": {"name": "Report problems to Zabbix administrators", "state": "absent"}, "msg": "missing required arguments: event_source"}
```
"""Construct operation message user.
        Args:
            operation: operation to construct the message user
        Returns:
            list: constructed operation message user or None if operation not found
        """
        if operation.get('send_to_users') is None:
            return None
        return [{
            'userid': self._zapi_wrapper.get_user_by_user_name(_user)['userid']
        } for _user in operation.get('send_to_users')]
    def _construct_opmessage_grp(self, operation):
        """Construct operation message group.
        Args:
            operation: operation to construct the message group
        Returns:
            list: constructed operation message group or None if operation not found
        """
        if operation.get('send_to_groups') is None:
            return None
        return [{
            'usrgrpid': self._zapi_wrapper.get_usergroup_by_usergroup_name(_group)['usrgrpid']
        } for _group in operation.get('send_to_groups')]
    def _construct_opcommand(self, operation):