Arguments can not be omitted

[peldax]

By specs, nullable arguments and input fields can be omitted from query, which is different from setting them to null.

• For input fields it is supported using PHP 7.4+ uninitialized property.
• For arguments, this is not possible without unnecessary magic/loss of type safety. Arguments are passed to resolve functions directly and it is not posslble to pass them uninitialized.

Graphpianator will always pass null as argument value for omitted arguments.