Zabbix

..F....... [ZBX-16153] fix 500 Internal Server Error when trying to preview pie/exploded graph without items

* commit '6743dbe2bc75e4255b248a9ebd2b09f25d853094':
  ..F....... [ZBX-16153] add ChangeLog
  ..F....... [ZBX-16153] fix validation rule for width
  ..F....... [ZBX-16153] change O_MAND to O_OPT
  ..F....... [ZBX-16153] fix unnecessary check
  ..F....... [ZBX-16153] 500 Internal Server Error when trying to preview pie/exploded graph without items

(cherry picked from commit 6bd1eee6f20319fef77a88e6afc55c8178c2c792)
(cherry picked from commit afe7af8a3fabb20d483bec17f11b51099e307704)