### 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.
WindowWrapper *wrapper = Object::cast_to<WindowWrapper>(p_dock);
	if (!wrapper) {
		_dock_make_float(p_dock, p_slot_index, false);
		wrapper = floating_docks[floating_docks.size() - 1];
	}
	wrapper->restore_window_from_saved_position(
			p_dock_dump.get("window_rect", Rect2i()),
			p_dock_dump.get("window_screen", -1),
			p_dock_dump.get("window_screen_rect", Rect2i()));
}
void EditorNode::_load_docks_from_config(Ref<ConfigFile> p_layout, const String &p_section) {
	Dictionary floating_docks_dump = p_layout->get_value(p_section, "dock_floating", Dictionary());
	bool restore_window_on_load = EDITOR_GET("interface/multi_window/restore_windows_on_load");
	for (int i = 0; i < DOCK_SLOT_MAX; i++) {
		if (!p_layout->has_section_key(p_section, "dock_" + itos(i + 1))) {
			continue;
		}
		Vector<String> names = String(p_layout->get_value(p_section, "dock_" + itos(i + 1))).split(",");
		for (int j = names.size() - 1; j >= 0; j--) {
			String name = names[j];
			
			int atidx = -1;
			Control *node = nullptr;
			for (int k = 0; k < DOCK_SLOT_MAX; k++) {
				if (!dock_slot[k]->has_node(name)) {
					continue;
				}
				node = Object::cast_to<Control>(dock_slot[k]->get_node(name));
				if (!node) {
					continue;