add hide functionality to menu components

[tabacitu]

WHY

BEFORE - What was wrong? What was happening before this PR?

We've implemented menu components in https://github.com/Laravel-Backpack/CRUD/pull/5135/ . One nice feature Pedro mentioned was the ability to hide a component, upon a condition. For example, when a user is not an admin, hide a menu item.

AFTER - What is happening after this PR?

You can do exactly that, by using the :hidden attribute on all components we have:

<!-- Users, Roles Permissions -->
@php
$is_admin = true;
@endphp

<x-backpack::menu-dropdown title="Authentication" icon="la la-group" :hidden="$is_admin">
    <x-backpack::menu-dropdown-item title="Users" icon="la la-user" :link="backpack_url('user')" />
    <x-backpack::menu-dropdown-item title="Roles" icon="la la-group" :link="backpack_url('role')" />
    <x-backpack::menu-dropdown-item title="Permissions" icon="la la-key" :link="backpack_url('permission')" />
</x-backpack::menu-dropdown>

HOW

How did you achieve that, in technical terms?

The hidden attribute can be:

• a boolean
• a Closure

That gets evaluated, and if it's false the PHP Component itself won't even load the blade file. No HTML gets written on page.

Is it a breaking change?

No - it's non-breaking. No PRs to themes is necessary.

[tabacitu]

The PR is 100% working but... I don't really like it:

• I'm not 100% sure we should use :hidden and not :visible as the component attribute name;
• I'm not 100% sure we are accepting all variable types that devs might want;
• I'm not 100% sure we should do this in the first place, since a dev can easily wrap the <x-something /> into a conditional; so from this point of view we aren't adding any features, we're just polluting the components for something that can already be done, very easily;

For the reasons above, I'm not going to spend any more time on this right now. We have a launch to finish, so let's do that. This is a COULD/SHOULD and non-breaking, so let's postpone thinking or talking about this until after the launch.

I've proven with this PR that it can be done in a non-breaking way. And convinced myself that https://github.com/Laravel-Backpack/CRUD/pull/5135/ is worth merging right away. So this was useful, but merging it... meeeh.

[pxpm]

Let's keep it simple.

Dev can wrap it in a conditional. 👍