### 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.
}
	} else {
		sdata->set_path(lpath, true); 
	}
	Node *new_scene = sdata->instantiate(p_set_inherited ? PackedScene::GEN_EDIT_STATE_MAIN_INHERITED : PackedScene::GEN_EDIT_STATE_MAIN);
	if (!new_scene) {
		sdata.unref();
		_dialog_display_load_error(lpath, ERR_FILE_CORRUPT);
		opening_prev = false;
		if (prev != -1) {
			set_current_scene(prev);
			editor_data.remove_scene(idx);
		}
		return ERR_FILE_CORRUPT;
	}
	if (p_set_inherited) {
		Ref<SceneState> state = sdata->get_state();
		state->set_path(lpath);
		new_scene->set_scene_inherited_state(state);
		new_scene->set_scene_file_path(String());
	}
	new_scene->set_scene_instance_state(Ref<SceneState>());
	set_edited_scene(new_scene);
	String config_file_path = EditorPaths::get_singleton()->get_project_settings_dir().path_join(p_scene.get_file() + "-editstate-" + p_scene.md5_text() + ".cfg");
	Ref<ConfigFile> editor_state_cf;
	editor_state_cf.instantiate();
	Error editor_state_cf_err = editor_state_cf->load(config_file_path);
	if (editor_state_cf_err == OK || editor_state_cf->has_section("editor_states")) {
		_load_editor_plugin_states_from_config(editor_state_cf);
	}