Zabbix

........S. [ZBXNEXT-6503] added protection of Zabbix Server from overloading by proxy data

Merge in ZBX/zabbix from feature/ZBXNEXT-6503-5.2 to release/5.2

* commit '076809490019b043d5086ce4885ce9c622bd269f':
  ........S. [ZBXNEXT-6503] Fix redundant include
  ........S. [ZBXNEXT-6503] fixed double failure response when disabling upload on active proxies,                           disabled 'cannot send data' warning on active proxies if data was refused because of disabled upload
  .......PS. [ZBXNEXT-6503] added protection of Zabbix Server from overloading by proxy data