I accidently submitted the same run so how do I get rid of it.

When I click the tree dots all i see is edit run and no delete run option.

Enter the pending run you want to delete (you can see it in your "Pending Actions" on the Hourglass icon of the site's navigation bar at the top), then at the right side of the run's description and stuff you should see three dots. Click on them and select "Delete run".

I believe your account needs to be seven days old before you can delete a run.

Alternatively, it's obvious on the mod's side when there's a duplicate submission and rejecting one as duplicate takes literally 10 seconds. If you can delete a duplicate submission yourself that's certainly courteous, but if you don't/can't, it's really not a big deal.