Transferring posts between communities is a lot more... complex... than you'd think.
Firstly, unless there's migration paths opened already (which there are not for the 'community' to use to move things to / from Ask UbuntU), migration of questions between communities requires the moderators on the origin site to intervene to moderate.
Secondly, the older the question, usually the more it's not likely to get migrated. That's a decision by the origin site's mods, yes, but the mods of the destination site can reject the migration by closing the question. Usually, 2 months is a cutoff for when a post can be migrated by the 'community', and though mods can do so at a later time they usually are very hesitant to migrate old posts.
Also, specifically for your question, you've also already given yourself your answer - you can do this by altering the .desktop's Exec line to pass in the option you want to not prompt.
You're also very very vague with your question - to quote muru from that post's comment:
"What do you mean by "manage this in the appropriate setting"?
... this means it's more likely that it'd be closed as "unclear what you're asking" here (by close voters), which would also reject the migration.
If you have every intention of wanting the post here on Ask Ubuntu, the solution is to delete (or flag for deletion) the other post on Super User, and repost here. Keep in mind that you have an upvote on your question, so that is also a factor.