Refactor `roles/zabbix_agent/tasks/userparameter.yml`

[flowerysong]

SUMMARY

Reduces duplication and improves efficiency of loops. Also removes a use of the deprecated zabbix_agent2_include variable.

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

zabbix_agent role

ADDITIONAL INFORMATION

[pyrodie18]

I like it....thanks a ton @flowerysong