NPE in canCompleteSwap if path doesn't exists

[LZD-PratyushBhatt]

Describe the bug

Currently when we call baseAccessor.getChildNames and if the path doesnt exists, swapOutResources is null, and we iterate over this which results in NPE

  "error" : "Cannot invoke \"java.util.List.iterator()\" because \"swapOutResources\" is null"
}

To Reproduce

Hit canCompleteSwap Rest and manually corrupt the path.

Expected behavior

NPEs should be handled, it should return true in this case as well.

Additional context

Add any other context about the problem here.