Zabbix

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

* commit '9d2fa1151f10ddda9f0176532d3a3c01ffddcd2a':
  ..F....... [DEV-4931] fixed a corner case with deeply nested expressions
  ..F....... [DEV-4931] add permission check for trigger expresison constructor
  ..F....... [DEV-4931] add permission check for trigger expression edit and test
  ..F....... [DEV-4931] reduced the number of recursive calls while building the expression tree