[5.8] Notification fake accepts custom channels

[dwightwatson]

When dispatching notifications now you have the option to pass in the channels you want to deliver that notification - overriding the channels returned from the notification's via method.

Unfortunately the NotificationFake doesn't support this use case - and it records the notifications having been sent over their default channels instead. This means that you cannot test that the notification was sent over the given channel instead.

This change is simply reflecting the implementation in NotificationSender into the fake.

Notification::fake();

$user->notify(new MessageReceived($message), [NexmoVoiceChannel::class]);

Notification::assertSentTo($user, MessageReceived::class, function ($notification, $channels) {
    return $channels[0] === NexmoVoiceChannel::class;
]);

For some additional context, my use-case is that the notification is usually delivered by email/text however a user might want to receive it via a phone call instead. An alternative approach might be to pass that in through the notification's constructor instead but that felt a little odd.