### 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.
if (update_spinner_step >= 8) {
					update_spinner_step = 0;
				}
				update_spinner_step_msec = tick;
				update_spinner_step_frame = frame + 1;
				
				if (EDITOR_GET("interface/editor/show_update_spinner")) {
					update_spinner->set_icon(gui_base->get_theme_icon("Progress" + itos(update_spinner_step + 1), SNAME("EditorIcons")));
				}
			}
			editor_selection->update();
			ResourceImporterTexture::get_singleton()->update_imports();
			if (settings_changed) {
				_update_title();
			}
			if (settings_changed) {
				_update_from_settings();
				settings_changed = false;
				emit_signal(SNAME("project_settings_changed"));
			}
			ResourceImporterTexture::get_singleton()->update_imports();
			bottom_panel_updating = false;
		} break;
		case NOTIFICATION_ENTER_TREE: {
			get_tree()->set_disable_node_threading(true); 
			Engine::get_singleton()->set_editor_hint(true);
			Window *window = get_window();
			if (window) {
				
				window->connect("titlebar_changed", callable_mp(this, &EditorNode::_titlebar_resized));