### 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.
}
				DisplayServer::get_singleton()->window_request_attention();
				break;
			}
			_save_external_resources();
			_discard_changes();
		} break;
		case SETTINGS_UPDATE_CONTINUOUSLY: {
			EditorSettings::get_singleton()->set("interface/editor/update_continuously", true);
			_update_update_spinner();
			show_accept(TTR("This option is deprecated. Situations where refresh must be forced are now considered a bug. Please report."), TTR("OK"));
		} break;
		case SETTINGS_UPDATE_WHEN_CHANGED: {
			EditorSettings::get_singleton()->set("interface/editor/update_continuously", false);
			_update_update_spinner();
		} break;
		case SETTINGS_UPDATE_SPINNER_HIDE: {
			EditorSettings::get_singleton()->set("interface/editor/show_update_spinner", false);
			_update_update_spinner();
		} break;
		case SETTINGS_PREFERENCES: {
			editor_settings_dialog->popup_edit_settings();
		} break;
		case SETTINGS_EDITOR_DATA_FOLDER: {
			OS::get_singleton()->shell_show_in_file_manager(EditorPaths::get_singleton()->get_data_dir(), true);
		} break;
		case SETTINGS_EDITOR_CONFIG_FOLDER: {
			OS::get_singleton()->shell_show_in_file_manager(EditorPaths::get_singleton()->get_config_dir(), true);
		} break;
		case SETTINGS_MANAGE_EXPORT_TEMPLATES: {