Simplify the check if admin can change password based on encryption status

Found by Psalm:
```
/home/runner/work/server/server/apps/settings/lib/Controller/UsersController.php:324:8:error - RedundantCondition: Type true for $isEncryptionModuleLoaded is never falsy
```

Signed-off-by: Morris Jobke <hey@morrisjobke.de>