### 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)
return;
		}
		
		if (!valid) {
			int idx = filter->get_selected();
			String flt = filters[idx].get_slice(";", 0);
			String ext = flt.get_slice(",", 0).strip_edges().get_extension();
			f += "." + ext;
		}
		if (file_name.begins_with(".")) { 
			error_dialog->set_text(TTR("Cannot save file with a name starting with a dot."));
			error_dialog->popup_centered(Size2(250, 80) * EDSCALE);
			return;
		}
		if (dir_access->file_exists(f) && !disable_overwrite_warning) {
			confirm_save->set_text(vformat(TTR("File \"%s\" already exists.\nDo you want to overwrite it?"), f));
			confirm_save->popup_centered(Size2(250, 80) * EDSCALE);
		} else {
			_save_to_recent();
			hide();
			emit_signal(SNAME("file_selected"), f);
		}
	}
}
void EditorFileDialog::_cancel_pressed() {
	file->set_text("");
	invalidate();
	hide();
}
void EditorFileDialog::_item_selected(int p_item) {