Zabbix

...G...... [ZBXNEXT-6651] added new item agent.variant for Agent and Agent2

Merge in ZBX/zabbix from feature/ZBXNEXT-6651-5.5 to master

* commit '0bdeac52d27040c1f5e9c8ebc75a1bbf34d0e4c3':
  ...G...... [ZBXNEXT-6651] fixed PR warning
  ...G...... [ZBXNEXT-6651] added integrqation tests
  ...G...... [ZBXNEXT-6651] changed items order
  ...G...... [ZBXNEXT-6651] added new item agent.variant for Agent
  ..F....... [ZBXNEXT-6651,ZBXNEXT-7012] added new item key "agent.variant" to the helper for selecting item keys