### 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)
Error change_dir_result = dir_access->change_dir(favorites->get_item_metadata(p_idx));
	if (change_dir_result != OK) {
		error_dialog->set_text(TTR("Favorited folder does not exist anymore and will be removed."));
		error_dialog->popup_centered(Size2(250, 50) * EDSCALE);
		bool res = (access == ACCESS_RESOURCES);
		Vector<String> favorited = EditorSettings::get_singleton()->get_favorites();
		String dir_to_remove = favorites->get_item_metadata(p_idx);
		bool found = false;
		for (int i = 0; i < favorited.size(); i++) {
			bool cres = favorited[i].begins_with("res://");
			if (cres != res) {
				continue;
			}
			if (favorited[i] == dir_to_remove) {
				found = true;
				break;
			}
		}
		if (found) {
			favorited.erase(favorites->get_item_metadata(p_idx));
			favorites->remove_item(p_idx);
			EditorSettings::get_singleton()->set_favorites(favorited);
		}
	} else {
		update_dir();
		invalidate();
		_push_history();
	}
}
void EditorFileDialog::_favorite_move_up() {