### 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.
return scene_tabs->get_current_tab();
}
void EditorNode::set_current_tab(int p_tab) {
	scene_tabs->set_current_tab(p_tab);
}
void EditorNode::_update_layouts_menu() {
	editor_layouts->clear();
	overridden_default_layout = -1;
	editor_layouts->reset_size();
	editor_layouts->add_shortcut(ED_SHORTCUT("layout/save", TTR("Save Layout")), SETTINGS_LAYOUT_SAVE);
	editor_layouts->add_shortcut(ED_SHORTCUT("layout/delete", TTR("Delete Layout")), SETTINGS_LAYOUT_DELETE);
	editor_layouts->add_separator();
	editor_layouts->add_shortcut(ED_SHORTCUT("layout/default", TTR("Default")), SETTINGS_LAYOUT_DEFAULT);
	Ref<ConfigFile> config;
	config.instantiate();
	Error err = config->load(EditorSettings::get_singleton()->get_editor_layouts_config());
	if (err != OK) {
		return; 
	}
	List<String> layouts;
	config.ptr()->get_sections(&layouts);
	for (const String &layout : layouts) {
		if (layout == TTR("Default")) {
			editor_layouts->remove_item(editor_layouts->get_item_index(SETTINGS_LAYOUT_DEFAULT));
			overridden_default_layout = editor_layouts->get_item_count();
		}
		editor_layouts->add_item(layout);
	}
}
void EditorNode::_layout_menu_option(int p_id) {