Undo / Redo performed notifications, even though undo / redo failed or was cancelled
E.g. when undoing 'create folder', but then selecting 'cancel', the notify still will be shown.
As well, happens on other operations ... to checked per operation.
--> For all asyn operations which are executed in an own job (copy, move, file/folder creation) this has to be fixed. Currently, it is just assumed that the operation will run fine if the pre-checks are ok.
Logic: If at least for one file of the file operation something was done, the notification should be shown.