### Godot version

4.1.dev (dc625bcbfc5b587ba8867481ee7a1f6a567c25d0)

### System information

Mageia 9, Linux

### Issue description

When importing a project in current `master`, the following error is raised for each asset that gets imported:
```
Attempting to parent and popup a dialog that already has a parent.
```

It seems to be raised once per asset, caused by the progress dialog.

CC @bruvzg

### Steps to reproduce

- Import a new project in Godot that contains importable assets, e.g. https://github.com/RPicster/godot4-demo-desert-light

### Minimal reproduction project

See above.
if (p_idx == 0) { 
		current_menu_option = FILE_EXPORT_MESH_LIBRARY;
		if (!editor_data.get_edited_scene_root()) {
			show_accept(TTR("This operation can't be done without a scene."), TTR("OK"));
			return;
		}
		List<String> extensions;
		Ref<MeshLibrary> ml(memnew(MeshLibrary));
		ResourceSaver::get_recognized_extensions(ml, &extensions);
		file_export_lib->clear_filters();
		for (const String &E : extensions) {
			file_export_lib->add_filter("*." + E);
		}
		file_export_lib->popup_file_dialog();
		file_export_lib->set_title(TTR("Export Mesh Library"));
	} else { 
		if (export_as_menu->get_item_submenu(p_idx).is_empty()) { 
			Callable callback = export_as_menu->get_item_metadata(p_idx);
			Callable::CallError ce;
			Variant result;
			callback.callp(nullptr, 0, result, ce);
			if (ce.error != Callable::CallError::CALL_OK) {
				String err = Variant::get_callable_error_text(callback, nullptr, 0, ce);
				ERR_PRINT("Error calling function from export_as menu: " + err);
			}
		}
	}
}
int EditorNode::_next_unsaved_scene(bool p_valid_filename, int p_start) {