### 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.
if (p_resource->get_path().is_resource_file()) {
			file->set_current_file(p_resource->get_path().get_file());
		} else {
			if (extensions.size()) {
				String resource_name_snake_case = p_resource->get_class().to_snake_case();
				file->set_current_file("new_" + resource_name_snake_case + "." + preferred.front()->get().to_lower());
			} else {
				file->set_current_file(String());
			}
		}
	} else if (!p_resource->get_path().is_empty()) {
		file->set_current_path(p_resource->get_path());
		if (extensions.size()) {
			String ext = p_resource->get_path().get_extension().to_lower();
			if (extensions.find(ext) == nullptr) {
				file->set_current_path(p_resource->get_path().replacen("." + ext, "." + extensions.front()->get()));
			}
		}
	} else if (preferred.size()) {
		String existing;
		if (extensions.size()) {
			String resource_name_snake_case = p_resource->get_class().to_snake_case();
			existing = "new_" + resource_name_snake_case + "." + preferred.front()->get().to_lower();
		}
		file->set_current_path(existing);
	}
	file->set_title(TTR("Save Resource As..."));
	file->popup_file_dialog();
}
void EditorNode::_menu_option(int p_option) {