Zabbix

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

* commit '66d6507bf97e92891b86717e0a5d0d71da37f7a2':
  ..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 constructor and test
  ..F....... [DEV-4931] add permission check for trigger expresison constructor