### 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)
switch (p_what) {
		case NOTIFICATION_THEME_CHANGED:
		case Control::NOTIFICATION_LAYOUT_DIRECTION_CHANGED:
		case NOTIFICATION_TRANSLATION_CHANGED: {
			_update_icons();
			invalidate();
		} break;
		case NOTIFICATION_PROCESS: {
			if (preview_waiting) {
				preview_wheel_timeout -= get_process_delta_time();
				if (preview_wheel_timeout <= 0) {
					preview_wheel_index++;
					if (preview_wheel_index >= 8) {
						preview_wheel_index = 0;
					}
					Ref<Texture2D> frame = theme_cache.progress[preview_wheel_index];
					preview->set_texture(frame);
					preview_wheel_timeout = 0.1;
				}
			}
		} break;