[GAMEPLAY] Damage over time preventing undo in shop

Enemy damage over time preventing early death shop purchases from being undone. Easiest example being Brand passive 'Deals damage' to a dead enemy champion, while the enemy champion is still 'taking damage' the shop removed the ability to refund items.

Step 1. Die to a champ while ignite/any d.o.t is still affected. Step 2. Quickly purchase an item Step 3. Cry that you cant refund that rabadons