### 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)
if (mode == FILE_MODE_OPEN_FILES) {
		String fbase = dir_access->get_current_dir();
		Vector<String> files;
		for (int i = 0; i < item_list->get_item_count(); i++) {
			if (item_list->is_selected(i)) {
				files.push_back(fbase.path_join(item_list->get_item_text(i)));
			}
		}
		if (files.size()) {
			_save_to_recent();
			hide();
			emit_signal(SNAME("files_selected"), files);
		}
		return;
	}
	String file_text = file->get_text();
	String f = file_text.is_absolute_path() ? file_text : dir_access->get_current_dir().path_join(file_text);
	if ((mode == FILE_MODE_OPEN_ANY || mode == FILE_MODE_OPEN_FILE) && dir_access->file_exists(f)) {
		_save_to_recent();
		hide();
		emit_signal(SNAME("file_selected"), f);
	} else if (mode == FILE_MODE_OPEN_ANY || mode == FILE_MODE_OPEN_DIR) {
		String path = dir_access->get_current_dir();
		path = path.replace("\\", "/");
		for (int i = 0; i < item_list->get_item_count(); i++) {
			if (item_list->is_selected(i)) {
				Dictionary d = item_list->get_item_metadata(i);