[2.0.14] being able to write a nil constant to decider combinators

[Quezler]

when you rightclick the 0 constant in a decider combinator you can clear it, if you blueprint this entity it'll keep working just fine.

but when you read the parameters and write it back via lua the nil/missing constant gets interpreted as the default 0 and it re-appears:

`/c game.player.opened.get_control_behavior().parameters = game.player.opened.get_control_behavior().parameters`

it would be nice if there was a way for lua to specify that the constant should remain empty.