### 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.
open_imported->hide();
	load_scene(open_import_request, true, true);
}
void EditorNode::_open_imported() {
	load_scene(open_import_request, true, false, true, true);
}
void EditorNode::dim_editor(bool p_dimming) {
	dimmed = p_dimming;
	gui_base->set_modulate(p_dimming ? Color(0.5, 0.5, 0.5) : Color(1, 1, 1));
}
bool EditorNode::is_editor_dimmed() const {
	return dimmed;
}
void EditorNode::open_export_template_manager() {
	export_template_manager->popup_manager();
}
void EditorNode::add_resource_conversion_plugin(const Ref<EditorResourceConversionPlugin> &p_plugin) {