Yes, the “Enable Sign in with Facebook” is only available for Native apps, since it requires the Android or IOS Facebook SDK, as stated here: https://auth0.com/docs/connections/nativesocial/facebook
In the meantime, you can still update your application by using the management API. You can use the PATCH /api/v2/clients/{id} with the following payload:
{
"native_social_login": {
"facebook": {
"enabled": true
}
}
}