"Which user type should be allowed" (negate) setting is implemented incorrectly

Problem/Motivation

The option has either the value 1 or 0, should be TRUE / FALSE instead
TRUE is "Allow the selected below" should be the other way around
When received from config we get a string ("0" / "1") this is very dangerous and the checks for this are completely incorrect:

      $actionType = $this->config->get('negate');
      $roles = array_filter($this->config->get('roles'));
      $userRoles = $this->currentUser->getRoles();
      if (isset($actionType) && !empty($roles) && !in_array('administrator', $userRoles)) {
        if (($actionType && empty(array_intersect($roles, $userRoles))) || (!$actionType && !empty(array_intersect($roles, $userRoles)))) {
          throw new AccessDeniedHttpException();
        }
      }

=> no need for "isset()" since it is always set and "if $actionType" will always result to true, because "0" as a string is TRUE.

Steps to reproduce

Proposed resolution

Fix this.

Remaining tasks

User interface changes

API changes

Data model changes