### Godot version

4.1.1

### System information

linux

### Issue description

- When favoriting a path in a `FileDialog`, clicking on it travels to `path/to/dir/`.
- When going up a level from there, it doesn't go to `path/to` but to `path/to/dir` (without the `/`).

[simplescreenrecorder-2023-08-18_09.38.37.webm](https://github.com/godotengine/godot/assets/71937306/00c20ad3-292f-4961-84ed-dbc64906df52)

The problem is either (or both) that:
 - loaded path has a trailing `/`
 - parent dir of `stuff/` is considered to be `stuff`

### Steps to reproduce

favorite a directory and use the feature to navigate to it

### Minimal reproduction project

any (i.e. the project manager's "new project" dialog has one)
dir->grab_focus();
				handled = true;
			}
			if (ED_IS_SHORTCUT("file_dialog/move_favorite_up", p_event)) {
				_favorite_move_up();
				handled = true;
			}
			if (ED_IS_SHORTCUT("file_dialog/move_favorite_down", p_event)) {
				_favorite_move_down();
				handled = true;
			}
			if (handled) {
				set_input_as_handled();
			}
		}
	}
}
void EditorFileDialog::set_enable_multiple_selection(bool p_enable) {
	item_list->set_select_mode(p_enable ? ItemList::SELECT_MULTI : ItemList::SELECT_SINGLE);
};
Vector<String> EditorFileDialog::get_selected_files() const {
	Vector<String> list;
	for (int i = 0; i < item_list->get_item_count(); i++) {
		if (item_list->is_selected(i)) {
			list.push_back(item_list->get_item_text(i));
		}
	}
	return list;
};
void EditorFileDialog::update_dir() {