### 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.
case SETTINGS_LAYOUT_DELETE: {
			current_menu_option = p_id;
			layout_dialog->set_title(TTR("Delete Layout"));
			layout_dialog->set_ok_button_text(TTR("Delete"));
			layout_dialog->set_name_line_enabled(false);
			layout_dialog->popup_centered();
		} break;
		case SETTINGS_LAYOUT_DEFAULT: {
			_load_docks_from_config(default_layout, "docks");
			_save_editor_layout();
		} break;
		default: {
			Ref<ConfigFile> config;
			config.instantiate();
			Error err = config->load(EditorSettings::get_singleton()->get_editor_layouts_config());
			if (err != OK) {
				return; 
			}
			_load_docks_from_config(config, editor_layouts->get_item_text(p_id));
			_save_editor_layout();
		}
	}
}
void EditorNode::_scene_tab_script_edited(int p_tab) {
	Ref<Script> scr = editor_data.get_scene_root_script(p_tab);
	if (scr.is_valid()) {
		InspectorDock::get_singleton()->edit_resource(scr);
	}
}
void EditorNode::_proceed_closing_scene_tabs() {