Zabbix

.......PS. [ZBX-18364] fixed fixed inconsistency with autoregistration behaviour for hosts without metadata on Oracle compared to other databases

Merge in ZBX/zabbix from feature/ZBX-18364-5.0 to release/5.0

* commit '63b15054c44910cd250ec8d685428ae5ccb91cc6':
  .......PS. [ZBX-18364] added function header for DBis_null() function
  .......PS. [ZBX-18364] fixed check for for host auto-registration
  .D........ [ZBX-18364] added ChangeLog entry
  .......PS. [ZBX-18364] fixed fixed inconsistency with autoregistration behaviour for hosts without metadata on Oracle compared to other databases