Prevent encoding/decoding objects that cannot be instantiated

[AThousandShips]

Ensures that encoding classes that cannot be instantiated errors, both when encoding and decoding

Could make the error message more descriptive but starting out simple

The decoding side isn't necessarily needed but it reduces the error count and could add a clearer message as well there (though I think the error return is better, ERR_INVALID_DATA over ERR_UNAVAILABLE)

• Closes: Objects of custom instance classes cannot be decoded by marshalls #84552

[Faless]

LGTM 👍 , thanks for looking into it 🏆

[YuriSizov]

Thanks!

[AThousandShips]

Thank you!