Fixed assertion editing a deleted proxy into a duplicate.

replaceItemWith() removed the edited row from the settings list without
restoring it first, so doing that to a row already marked deleted - which
is not in that list at all - failed the Assert. Its sibling
replaceItemValue() has restored first all along.

_list is also a vector, so erasing the edited item shifts everything
after it and left the iterator for the duplicate naming a different item
- or one past the end when the duplicate was last. Read its id and
deleted flag before the erase; everything after it works by id anyway.