Fix C# array null handling

[SaNeOr]

close #82362

[RedworkDE]

I do not think that this is the correct fix as there isn't really a null Span, instead null equals to an empty span, thus I'd argue that the throw from the Array constructor as currently there is no way to create a Godot.Array from an empty array. If the behavior of converting a null StringName[] to a nil variant is desired such a check has to be added at a different point.

[SaNeOr]

I do not think that this is the correct fix as there isn't really a null Span, instead null equals to an empty span, thus I'd argue that the throw from the Array constructor as currently there is no way to create a Godot.Array from an empty array. If the behavior of converting a null StringName[] to a nil variant is desired such a check has to be added at a different point.

But the way it actually works at the moment is that if you pass null directly to CreateFromArray, it still returns default(godot_variant).

[SaNeOr]

@RedworkDE Is it correct to refer to a new array when span is empty?

[akien-mga]

Superseded by #89756. Thanks for the contribution!