'Created at' on Fee/Fine Details should be a '-' if it doesn't exist

When we introduced automated fees/fines, we ran into the situation where the 'Created at' column appears as blank (as shown in attached screen print Created-at-currently.jpg). If the 'action' record does not include a value for 'Created at', we should display a 'hypen' (as shown in attached screen print Created-at-with-hypen.jpg).