Paste Select Fix

Makes it so when you undo a paste the objects you had selected before the paste get reselected.

For example, if you copy & paste a group of objects and undo the copy & paste, the original objects would be reselected. This is different from vanilla geometry dash where the pasted objects would just be deleted and you would be left with nothing selected, which can be annoying if you accidently pressed the copy and paste button as you would have to start selecting the objects again.