### 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_error) {
		switch (p_error) {
			case ERR_CANT_OPEN: {
				show_accept(vformat(TTR("Can't open file '%s'. The file could have been moved or deleted."), p_file.get_file()), TTR("OK"));
			} break;
			case ERR_PARSE_ERROR: {
				show_accept(vformat(TTR("Error while parsing file '%s'."), p_file.get_file()), TTR("OK"));
			} break;
			case ERR_FILE_CORRUPT: {
				show_accept(vformat(TTR("Scene file '%s' appears to be invalid/corrupt."), p_file.get_file()), TTR("OK"));
			} break;
			case ERR_FILE_NOT_FOUND: {
				show_accept(vformat(TTR("Missing file '%s' or one its dependencies."), p_file.get_file()), TTR("OK"));
			} break;
			default: {
				show_accept(vformat(TTR("Error while loading file '%s'."), p_file.get_file()), TTR("OK"));
			} break;
		}
	}
}
void EditorNode::_load_editor_plugin_states_from_config(const Ref<ConfigFile> &p_config_file) {