Zabbix

..F....... [DEV-4931] reduced the number of recursive calls while building the expression tree

* commit '3b8c2e7a3dfd315e52619fd93b4363d2d3a27fb9':
  ..F....... [DEV-4931] fixed a corner case with deeply nested expressions
  ..F....... [DEV-4931] reduced the number of recursive calls while building the expression tree
  ..F....... [DEV-4931] add permission check for trigger expression edit and test