### 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.
disk_changed_list->clear();
	TreeItem *r = disk_changed_list->create_item();
	disk_changed_list->set_hide_root(true);
	bool need_reload = false;
	
	for (int i = 0; i < editor_data.get_edited_scene_count(); i++) {
		Ref<DirAccess> da = DirAccess::create(DirAccess::ACCESS_RESOURCES);
		if (editor_data.get_scene_path(i) == "" || !da->file_exists(editor_data.get_scene_path(i))) {
			continue;
		}
		uint64_t last_date = editor_data.get_scene_modified_time(i);
		uint64_t date = FileAccess::get_modified_time(editor_data.get_scene_path(i));
		if (date > last_date) {
			TreeItem *ti = disk_changed_list->create_item(r);
			ti->set_text(0, editor_data.get_scene_path(i).get_file());
			need_reload = true;
		}
	}
	String project_settings_path = ProjectSettings::get_singleton()->get_resource_path().path_join("project.godot");
	if (FileAccess::get_modified_time(project_settings_path) > ProjectSettings::get_singleton()->get_last_saved_time()) {
		TreeItem *ti = disk_changed_list->create_item(r);
		ti->set_text(0, "project.godot");
		need_reload = true;
	}
	if (need_reload) {
		disk_changed->call_deferred(SNAME("popup_centered_ratio"), 0.3);
	}
}
void EditorNode::_resave_scenes(String p_str) {