Zabbix

...G...... [ZBX-19267] moved check for empty property value after check if property is "key"

Merge in ZBX/zabbix from feature/ZBX-19267-7.0 to release/7.0

* commit 'd060db1b5d44f4b244b9cb78311270d7ae0a5c4c':
  ...G...... [ZBX-19267] added comments and fixed ChangeLog entry
  ...G...... [ZBX-19267] reworked code following guidelines
  ...G...... [ZBX-19267] moved check for empty property value after check if property is "key"