### 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 filters;
}
String EditorFileDialog::get_current_dir() const {
	return dir_access->get_current_dir();
}
String EditorFileDialog::get_current_file() const {
	return file->get_text();
}
String EditorFileDialog::get_current_path() const {
	return dir_access->get_current_dir().path_join(file->get_text());
}
void EditorFileDialog::set_current_dir(const String &p_dir) {
	if (p_dir.is_relative_path()) {
		dir_access->change_dir(OS::get_singleton()->get_resource_dir());
	}
	dir_access->change_dir(p_dir);
	update_dir();
	invalidate();
}
void EditorFileDialog::set_current_file(const String &p_file) {
	file->set_text(p_file);
	update_dir();
	invalidate();
	_focus_file_text();
	if (is_visible()) {
		_request_single_thumbnail(get_current_dir().path_join(get_current_file()));
	}
}
void EditorFileDialog::set_current_path(const String &p_path) {