### Godot version

4.1.beta (7b1387ff2)

### System information

Mageia 9, Linux

### Issue description

When opening an empty project in latest `master`, I get these errors:
```
ERROR: Index p_idx = -1 is out of bounds (edited_scene.size() = 1).
   at: get_scene_path (editor/scu/../editor_data.cpp:880)
ERROR: Index p_idx = -1 is out of bounds (edited_scene.size() = 1).
   at: check_and_update_scene (editor/scu/../editor_data.cpp:683)
ERROR: Index p_idx = -1 is out of bounds (edited_scene.size() = 1).
   at: set_edited_scene (editor/scu/../editor_data.cpp:745)
```

Possibly related to recent changes to restore past sessions, but there's nothing to restore in this case?

### Steps to reproduce

- Create a new project, edit it
- Quit to project manager
- Re-open the newly created project -> errors

### Minimal reproduction project

Empty project.
eta.exitcode = 255;
	int prev_len = 0;
	eta.execute_output_thread.start(_execute_thread, &eta);
	while (!eta.done.is_set()) {
		{
			MutexLock lock(eta.execute_output_mutex);
			if (prev_len != eta.output.length()) {
				String to_add = eta.output.substr(prev_len, eta.output.length());
				prev_len = eta.output.length();
				execute_outputs->add_text(to_add);
				DisplayServer::get_singleton()->process_events(); 
				Main::iteration();
			}
		}
		OS::get_singleton()->delay_usec(1000);
	}
	eta.execute_output_thread.wait_to_finish();
	execute_outputs->add_text("\nExit Code: " + itos(eta.exitcode));
	if (execute_output_dialog) {
		if (p_close_on_errors && eta.exitcode != 0) {
			execute_output_dialog->hide();
		}
		if (p_close_on_ok && eta.exitcode == 0) {
			execute_output_dialog->hide();
		}
		execute_output_dialog->get_ok_button()->set_disabled(false);
	}
	return eta.exitcode;
}
void EditorNode::notify_settings_changed() {