### 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)
int current = p_item;
	if (current < 0 || current >= item_list->get_item_count()) {
		return;
	}
	Dictionary d = item_list->get_item_metadata(current);
	if (d["dir"]) {
		dir_access->change_dir(d["name"]);
		callable_mp(this, &EditorFileDialog::update_file_list).call_deferred();
		callable_mp(this, &EditorFileDialog::update_dir).call_deferred();
		_push_history();
	} else {
		_action_pressed();
	}
}
void EditorFileDialog::_item_list_item_rmb_clicked(int p_item, const Vector2 &p_pos, MouseButton p_mouse_button_index) {
	if (p_mouse_button_index != MouseButton::RIGHT) {
		return;
	}
	
	item_menu->clear();
	item_menu->reset_size();
	
	bool single_item_selected = item_list->get_selected_items().size() == 1;
	
	bool allow_delete = true;
	for (int i = 0; i < item_list->get_item_count(); i++) {
		if (!item_list->is_selected(i)) {