### 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.
current_menu_option = p_option;
	tab_closing_idx = p_tab;
	Node *scene = editor_data.get_edited_scene_root(p_tab);
	if (!scene) {
		_discard_changes();
		return;
	}
	bool unsaved = EditorUndoRedoManager::get_singleton()->is_history_unsaved(editor_data.get_scene_history_id(p_tab));
	if (unsaved) {
		if (get_current_tab() != p_tab) {
			set_current_scene(p_tab);
		}
		String scene_filename = scene->get_scene_file_path();
		if (current_menu_option == RELOAD_CURRENT_PROJECT) {
			save_confirmation->set_ok_button_text(TTR("Save & Reload"));
			save_confirmation->set_text(vformat(TTR("Save changes to '%s' before reloading?"), !scene_filename.is_empty() ? scene_filename : "unsaved scene"));
		} else {
			save_confirmation->set_ok_button_text(TTR("Save & Close"));
			save_confirmation->set_text(vformat(TTR("Save changes to '%s' before closing?"), !scene_filename.is_empty() ? scene_filename : "unsaved scene"));
		}
		save_confirmation->reset_size();
		save_confirmation->popup_centered();
	} else {
		_discard_changes();
	}
	save_editor_layout_delayed();
	_update_scene_tabs();
}
void EditorNode::_scene_tab_hovered(int p_tab) {