Select field [mountedActionsData.0.brand_id] must have a [createOptionUsing()] closure set.

  return $form
            ->schema([
                TextInput::make('name')
                    ->required()
                    ->maxLength(255)
                    ->minLength(2),
                Select::make('brand_id')
                    ->label('Brand')
                    ->multiple()
                    ->searchable()
                    ->required()
                    ->options(Brand::pluck('name', 'id'))
                    ->preload()
                    ->createOptionForm([
                        TextInput::make('name')
                            ->required()
                            ->label('New Brand'),
                    ]),
                Select::make('subbrand_id')
                    ->label('Subbrand')
                    ->multiple()
                    ->searchable()
                    ->options(Subbrand::pluck('name', 'id'))
                    ->columnSpan('full')
                    ->preload()
                    ->createOptionForm([
                        TextInput::make('name')
                            ->required()
                            ->label('New Subbrand'),
                    ]),
            ]);

  return $form
            ->schema([
                TextInput::make('name')
                    ->required()
                    ->maxLength(255)
                    ->minLength(2),
                Select::make('brand_id')
                    ->label('Brand')
                    ->multiple()
                    ->searchable()
                    ->required()
                    ->options(Brand::pluck('name', 'id'))
                    ->preload()
                    ->createOptionForm([
                        TextInput::make('name')
                            ->required()
                            ->label('New Brand'),
                    ]),
                Select::make('subbrand_id')
                    ->label('Subbrand')
                    ->multiple()
                    ->searchable()
                    ->options(Subbrand::pluck('name', 'id'))
                    ->columnSpan('full')
                    ->preload()
                    ->createOptionForm([
                        TextInput::make('name')
                            ->required()
                            ->label('New Subbrand'),
                    ]),
            ]);