### 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.
save_all_scenes();
	ProjectSettings::get_singleton()->save();
	disk_changed->hide();
}
void EditorNode::_reload_modified_scenes() {
	int current_idx = editor_data.get_edited_scene();
	for (int i = 0; i < editor_data.get_edited_scene_count(); i++) {
		if (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) {
			String filename = editor_data.get_scene_path(i);
			editor_data.set_edited_scene(i);
			_remove_edited_scene(false);
			Error err = load_scene(filename, false, false, true, false, true);
			if (err != OK) {
				ERR_PRINT(vformat("Failed to load scene: %s", filename));
			}
			editor_data.move_edited_scene_to_index(i);
		}
	}
	set_current_scene(current_idx);
	_update_scene_tabs();
	disk_changed->hide();
}
void EditorNode::_reload_project_settings() {