##### SUMMARY
`esc_period` is mandatory even with `state: absent` - should be optional in that case.

##### 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"
    event_source: 'trigger'
    state: absent
```

##### EXPECTED RESULTS
Action, if exists, is removed.

##### ACTUAL RESULTS
```paste below
"msg": "missing required arguments: esc_period"
```
"""Main ansible module function
    """
    module = AnsibleModule(
        argument_spec=dict(
            server_url=dict(type='str', required=True, aliases=['url']),
            login_user=dict(type='str', required=True),
            login_password=dict(type='str', required=True, no_log=True),
            http_login_user=dict(type='str', required=False, default=None),
            http_login_password=dict(type='str', required=False, default=None, no_log=True),
            validate_certs=dict(type='bool', required=False, default=True),
            esc_period=dict(type='int', required=True),
            timeout=dict(type='int', default=10),
            name=dict(type='str', required=True),
            event_source=dict(type='str', required=True, choices=['trigger', 'discovery', 'auto_registration', 'internal']),
            state=dict(type='str', required=False, default='present', choices=['present', 'absent']),
            status=dict(type='str', required=False, default='enabled', choices=['enabled', 'disabled']),
            pause_in_maintenance=dict(type='bool', required=False, default=True),
            default_message=dict(type='str', required=False, default=''),
            default_subject=dict(type='str', required=False, default=''),
            recovery_default_message=dict(type='str', required=False, default=''),
            recovery_default_subject=dict(type='str', required=False, default=''),
            acknowledge_default_message=dict(type='str', required=False, default=''),
            acknowledge_default_subject=dict(type='str', required=False, default=''),
            conditions=dict(
                type='list',
                required=False,