##### 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"
```
from __future__ import absolute_import, division, print_function
__metaclass__ = type
ANSIBLE_METADATA = {
    'metadata_version': '1.1',
    'status': ['preview'],
    'supported_by': 'community'
}
DOCUMENTATION = '''
---
module: zabbix_action
short_description: Create/Delete/Update Zabbix actions
version_added: "2.8"
description:
    - This module allows you to create, modify and delete Zabbix actions.
author:
    - Ruben Tsirunyan (@rubentsirunyan)
    - Ruben Harutyunov (@K-DOT)
requirements: