### 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.
_menu_option_confirm(p_option, false);
}
void EditorNode::_menu_confirm_current() {
	_menu_option_confirm(current_menu_option, true);
}
void EditorNode::_dialog_display_save_error(String p_file, Error p_error) {
	if (p_error) {
		switch (p_error) {
			case ERR_FILE_CANT_WRITE: {
				show_accept(TTR("Can't open file for writing:") + " " + p_file.get_extension(), TTR("OK"));
			} break;
			case ERR_FILE_UNRECOGNIZED: {
				show_accept(TTR("Requested file format unknown:") + " " + p_file.get_extension(), TTR("OK"));
			} break;
			default: {
				show_accept(TTR("Error while saving."), TTR("OK"));
			} break;
		}
	}
}
void EditorNode::_dialog_display_load_error(String p_file, Error p_error) {