Right now items created by a Flow are 'Created by' the account the Flow creator used to create the connection the action used.
Often, as in the case of the VST Create Work Item action there is then no 'hook' to know who ACTUALLY created the item. In my case a powerApp creates a SharePoint list item. A flow then takes that does some stuff to it and then uses that data to create a VST Work Item. My customer's strong pref is to have this VST item be created by the person that was operation the PowerApp.
Some of this is so that we then have some way of using Flow to notifiy the creator of changes to the item which is currently cumbersom and manual in VST.