Add proper typing for option conditions

[manuel3108]

Source svelte-add/svelte-add#397

Option types for option conditions are currently of type any, because we did not manage to implement that in the first place. But it should be possible to implement this, as other tools are doing this.
Initially implement by svelte-add/svelte-add#379
Review Conversation: svelte-add/svelte-add#379 (comment)