### 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.
project_menu->add_child(vcs_actions_menu);
	project_menu->set_item_submenu(project_menu->get_item_index(VCS_MENU), "Version Control");
	add_editor_plugin(memnew(AudioBusesEditorPlugin(audio_bus_editor)));
	for (int i = 0; i < EditorPlugins::get_plugin_count(); i++) {
		add_editor_plugin(EditorPlugins::create(i));
	}
	for (const StringName &extension_class_name : GDExtensionEditorPlugins::get_extension_classes()) {
		add_extension_editor_plugin(extension_class_name);
	}
	GDExtensionEditorPlugins::editor_node_add_plugin = &EditorNode::add_extension_editor_plugin;
	GDExtensionEditorPlugins::editor_node_remove_plugin = &EditorNode::remove_extension_editor_plugin;
	for (int i = 0; i < plugin_init_callback_count; i++) {
		plugin_init_callbacks[i]();
	}
	resource_preview->add_preview_generator(Ref<EditorTexturePreviewPlugin>(memnew(EditorTexturePreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorImagePreviewPlugin>(memnew(EditorImagePreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorPackedScenePreviewPlugin>(memnew(EditorPackedScenePreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorMaterialPreviewPlugin>(memnew(EditorMaterialPreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorScriptPreviewPlugin>(memnew(EditorScriptPreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorAudioStreamPreviewPlugin>(memnew(EditorAudioStreamPreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorMeshPreviewPlugin>(memnew(EditorMeshPreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorBitmapPreviewPlugin>(memnew(EditorBitmapPreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorFontPreviewPlugin>(memnew(EditorFontPreviewPlugin)));
	resource_preview->add_preview_generator(Ref<EditorGradientPreviewPlugin>(memnew(EditorGradientPreviewPlugin)));
	{
		Ref<StandardMaterial3DConversionPlugin> spatial_mat_convert;
		spatial_mat_convert.instantiate();
		resource_conversion_plugins.push_back(spatial_mat_convert);
		Ref<ORMMaterial3DConversionPlugin> orm_mat_convert;
		orm_mat_convert.instantiate();