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"

(cherry picked from commit 9bf00d9a5334f9b02ff803e507b972556737369d)
(cherry picked from commit 7d867a3719ac3426560bcb65d23b25800c0571a9)
(cherry picked from commit ee31798d42165d56992faee07692076e91ae0510)
(cherry picked from commit 546ce65fd46390d20b2f64cc5a9b3c3c6ecd3e5c)