Removes an unneeded placeholder cell from the table view.
- iOS 11.0+
- Mac Catalyst 13.0+
true if the placeholder cell was removed, or
false if the cell was no longer in the table view.
Call this method on your app's main thread to remove a placeholder cell without swapping in a new cell. You might call this method if the user chooses to undo the insertion of a cell or if the contents of the table view changed.