wger: Trainer Privilege Escalation - Improper Privilege Management

wger is a free, open-source workout and fitness manager. Prior to version 2.6, a user with only the `gym_trainer` permission can deactivate any account in the same gym, including `gym_manager` and `general_gym_manager` accounts. The `UserDeactivateView` grants access to anyone holding any one of `gym.manage_gym`, `gym.manage_gyms`, or `gym.gym_trainer` (OR logic via `WgerMultiplePermissionRequiredMixin`), and performs no privilege-hierarchy check to prevent a lower-privileged role from disabling a higher-privileged one. Version 2.6 fixes the issue.