Steps to reproduce:

1. Create user role with user type "Super admin"
2. Create new user and assign to him the created role
3. Login as created user
4. Go to Administration -> User roles
5. Click on current user's role to open edit form
6. Change the "User type" to "Admin"
7. Press "Update"

Result:
Access denied message is shown and user type of user's role was changed to "Admin".

Expected:
The user's role edit form is shown with message like "The user type for current user's role is not allowed to change." in error box and user type was not updated to lower.