### 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 export_as_menu;
}
void EditorNode::_global_menu_scene(const Variant &p_tag) {
	int idx = (int)p_tag;
	scene_tabs->set_current_tab(idx);
}
void EditorNode::_global_menu_new_window(const Variant &p_tag) {
	if (OS::get_singleton()->get_main_loop()) {
		List<String> args;
		args.push_back("-p");
		OS::get_singleton()->create_instance(args);
	}
}
void EditorNode::_dropped_files(const Vector<String> &p_files) {
	String to_path = ProjectSettings::get_singleton()->globalize_path(FileSystemDock::get_singleton()->get_current_directory());
	_add_dropped_files_recursive(p_files, to_path);
	EditorFileSystem::get_singleton()->scan_changes();
}
void EditorNode::_add_dropped_files_recursive(const Vector<String> &p_files, String to_path) {