In order to add validation for custom abilities permissions, the feature flag check should be converted to an instance type flag. This will allow us to add a validator for enabled permissions when creating or updating member roles. Currently, the feature flag check is set to use the `current_user` as the subject to check whether permissions are enabled, but this leads to inconsistent behavior for users in a namespace when a feature flag is partially rolled out. Another alternative would be to use the namespace as the feature flag subject. This will be more complicated to implement, but it will provide a more consistent experience for users in a project.