Zabbix

.......... [DEV-4627] enabled PHPUnit warnings

Merge in ZBX/zabbix from feature/DEV-4627-6.0 to release/6.0

* commit 'd6f8c52cf5fc0e26c70681b207e1806320fc511a':
  .......... [DEV-4627] removed unused namespace imports; removed unused test class
  .......... [DEV-4627] fixed callback issues; updated element selector
  .......... [DEV-4627] fixed callback issues; updated element selectors; fixed issues related to detect function
  .......... [DEV-4627] updated detect function; removed zbxAddWarning from CLegacyWebTest
  .......... [DEV-4627] added description
  .......... [DEV-4627] updated PHPUnit exception class
  .......... [DEV-4627] enabled PHPUNIT_REPORT_WARNINGS