Don't create extra tasks when unpublishing if they already exist.
Don't create extra tasks when unpublishing if they already exist.

For https://unisubs.sifterapp.com/projects/12298/issues/591158/comments

ofer43211/unisubs,ofer43211/unisubs,eloquence/unisubs,norayr/unisubs,eloquence/unisubs,ReachingOut/unisubs,ujdhesa/unisubs,pculture/unisubs,pculture/unisubs,eloquence/unisubs,eloquence/unisubs,pculture/unisubs,wevoice/wesub,ReachingOut/unisubs,ofer43211/unisubs,ujdhesa/unisubs,ofer43211/unisubs,ujdhesa/unisubs,wevoice/wesub,wevoice/wesub,ujdhesa/unisubs,norayr/unisubs,norayr/unisubs,norayr/unisubs,pculture/unisubs,ReachingOut/unisubs,wevoice/wesub,ReachingOut/unisubs