### 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.
ResourceImporterScene::add_importer(import_obj2);
			Ref<EditorSceneFormatImporterESCN> import_escn;
			import_escn.instantiate();
			ResourceImporterScene::add_importer(import_escn);
		}
		Ref<ResourceImporterBitMap> import_bitmap;
		import_bitmap.instantiate();
		ResourceFormatImporter::get_singleton()->add_importer(import_bitmap);
	}
	{
		Ref<EditorInspectorDefaultPlugin> eidp;
		eidp.instantiate();
		EditorInspector::add_inspector_plugin(eidp);
		Ref<EditorInspectorRootMotionPlugin> rmp;
		rmp.instantiate();
		EditorInspector::add_inspector_plugin(rmp);
		Ref<EditorInspectorVisualShaderModePlugin> smp;
		smp.instantiate();
		EditorInspector::add_inspector_plugin(smp);
	}
	editor_selection = memnew(EditorSelection);
	EditorFileSystem *efs = memnew(EditorFileSystem);
	add_child(efs);
	
	FileDialog::get_icon_func = _file_dialog_get_icon;
	FileDialog::register_func = _file_dialog_register;
	FileDialog::unregister_func = _file_dialog_unregister;
	EditorFileDialog::get_icon_func = _file_dialog_get_icon;
	EditorFileDialog::register_func = _editor_file_dialog_register;
	EditorFileDialog::unregister_func = _editor_file_dialog_unregister;