### 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)
global_remove_dialog = memnew(ConfirmationDialog);
	global_remove_dialog->set_text(TTR("Remove the selected files? For safety only files and empty directories can be deleted from here. (Cannot be undone.)\nDepending on your filesystem configuration, the files will either be moved to the system trash or deleted permanently."));
	global_remove_dialog->connect("confirmed", callable_mp(this, &EditorFileDialog::_delete_files_global));
	add_child(global_remove_dialog);
	makedialog = memnew(ConfirmationDialog);
	makedialog->set_title(TTR("Create Folder"));
	VBoxContainer *makevb = memnew(VBoxContainer);
	makedialog->add_child(makevb);
	makedirname = memnew(LineEdit);
	makedirname->set_structured_text_bidi_override(TextServer::STRUCTURED_TEXT_FILE);
	makevb->add_margin_child(TTR("Name:"), makedirname);
	add_child(makedialog);
	makedialog->register_text_enter(makedirname);
	makedialog->connect("confirmed", callable_mp(this, &EditorFileDialog::_make_dir_confirm));
	error_dialog = memnew(AcceptDialog);
	add_child(error_dialog);
	update_filters();
	update_dir();
	set_hide_on_ok(false);
	vbox = vbc;
	if (register_func) {
		register_func(this);
	}
}
EditorFileDialog::~EditorFileDialog() {
	if (unregister_func) {
		unregister_func(this);
	}
}