### 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 (DisplayServer::get_singleton()->window_can_draw()) {
				ProjectSettings::get_singleton()->save();
			}
			_titlebar_resized();
			
		} break;
		case NOTIFICATION_APPLICATION_FOCUS_IN: {
			
			OS::get_singleton()->set_low_processor_usage_mode_sleep_usec(int(EDITOR_GET("interface/editor/low_processor_mode_sleep_usec")));
			EditorFileSystem::get_singleton()->scan_changes();
			_scan_external_changes();
		} break;
		case NOTIFICATION_APPLICATION_FOCUS_OUT: {
			
			if (EDITOR_GET("interface/editor/save_on_focus_loss")) {
				_menu_option_confirm(FILE_SAVE_SCENE, false);
			}
			
			OS::get_singleton()->set_low_processor_usage_mode_sleep_usec(int(EDITOR_GET("interface/editor/unfocused_low_processor_mode_sleep_usec")));
		} break;
		case NOTIFICATION_WM_ABOUT: {
			show_about();
		} break;
		case NOTIFICATION_WM_CLOSE_REQUEST: {
			_menu_option_confirm(FILE_QUIT, false);
		} break;
		case EditorSettings::NOTIFICATION_EDITOR_SETTINGS_CHANGED: {
			scene_tabs->set_tab_close_display_policy((TabBar::CloseButtonDisplayPolicy)EDITOR_GET("interface/scene_tabs/display_close_button").operator int());
			FileDialog::set_default_show_hidden_files(EDITOR_GET("filesystem/file_dialog/show_hidden_files"));
			EditorFileDialog::set_default_show_hidden_files(EDITOR_GET("filesystem/file_dialog/show_hidden_files"));