Add visible(bool) to Dropdown and DropdownItem

[Mister-42]

Since Dropdown and its items are often used in Nav. It would be helpful if there's an built-in way to show/hide menus/items based on app logic (for example $currentUser->isGuest()).
Additionaly, it would add consistency with NavLink: https://github.com/yiisoft/bootstrap5/blob/master/src/NavLink.php#L378

[terabytesoftw]

Add a code example of what you want to do, thanks.

[Mister-42]

echo Nav::widget()
    ->items(
        NavLink::to("Link")
            ->visible($this->currentUser->isGuest()), # this `visible` fucntion is already implemented and working
        Dropdown::widget()->togglerContent('Dropdown')
            ->visible(!$this->currentUser->isGuest()) # this `visible` function is currently not present
            ->items(
                DropdownItem::link('Link only for admin')
                    ->visible($this->currentUser->getId() === "1"), # this `visible` function is currently not present
                DropdownItem::link('Link for anyone logged in')
            ),
    );