Zabbix

A.F....... [ZBX-26089] added the validation for the advanced custom labels in Network map

* commit '19c6c7d6e1ad36b1f04bf59c71d235e7ea4b06d3':
  A.F....... [ZBX-26089] changed variable name from max_label_name_length to label_string_length, updated code style
  A.F....... [ZBX-26089] updated text in Changelog file
  A.F....... [ZBX-26089] updated error message, added check undefined index in the $map_labels array
  A.F....... [ZBX-26089] replaced ucfirst with mb_ucfirst for new translation string
  ..F....... [ZBX-26089] changed text for the new translation string
  ..F....... [ZBX-26089] added the validation for the advanced custom labels during creating Network map
  ..F....... [ZBX-26089] added the validation for the advanced custom labels in Network map