Allow to disable a modal trigger

[CharlieEtienne]

Description

Currently there is no way to prevent a modal from being triggered. Even if the trigger button is disabled, the modal would still open, as in this example:

<x-filament::modal id="modalTest">
    <x-slot name="trigger">
        <x-filament::button :disabled="true">I'm disabled</x-filament::button>
    </x-slot>
    Hello, I'm a modal
</x-filament::modal>

This PR lets users disable the trigger element like this:

<x-filament::modal id="modalTest">
    <x-slot name="trigger" :disabled="true">
        <x-filament::button :disabled="true">I'm disabled</x-filament::button>
    </x-slot>
    Hello, I'm a modal
</x-filament::modal>

It also adds documentation for this change.

Functional changes

• Code style has been fixed by running the composer cs command.
• Changes have been tested to not break existing functionality.
• Documentation is up-to-date.

[danharrin]

Thanks