DolphinViewContainer: Delay changing the url

DolphinViewContainer: Delay changing the url

KCoreDirLister::itemsDeleted() signal is being emitted twice for the
same url. This results in Dolphin displaying an incorrect location.
Delay changing the url instead of delaying
DolphinView::currentDirectoryRemoved() so that the check for current
directory being removed in KFileItemModel::slotItemsDeleted() occurs
correctly, while still ensuring that KCoreDirLister is not prematurely
modified.

BUG: 492277, BUG: 473377