Hide model fields from gql schema if they are never allowed to be seen by the abilities

```
user model {
  id string
  secret string
}
```

scenario 1:
  ability1: allows access to all fields for logged in users
  ability2: allows access to the id for everyone
=> all fields should be in the schema


scenario 2:
  ability1: allows access to id for logged in users
  ability2: allows access to the id for everyone
=> secret should not be in the schema since it can never be seen anyway