[9.x] Allow maintenance mode events to be listened to in closure based listeners

[lioneaglesolutions]

I'm not sure if this is a bug as such but I ran into this today.

I was trying to listen to MaintenanceModeDisabled::class and broadcast this (which I don't think works in maintenance mode anyway) but nonetheless, was faced with this error when registering my listener as usual, with the event type-hinted in the handler so I could then dispatch my own event to broadcast it;

class MaintenanceModeDisabledListener
{
    public function handle(\Illuminate\Foundation\Events\MaintenanceModeDisabled $event)
    {
        MyCustomMaintenanceModeDisabledEvent::dispatch();
    }
}

This was met with an error;
Too few arguments to function ....\MaintenanceModeDisabledListener::handle(), 0 passed in .../vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php on line 441 and exactly 1 expected

Upon further experimenting I realised that the following listener would also fail and mean you couldn't listen to these events using closures;

Event::listen(function (MaintenanceModeDisabled $event) {
    // custom logic here
});

This behaviour is confirmed with the following failing tests;

public function testDisabledEventCanBeListenedTo()
{
    file_put_contents(
        storage_path('framework/down'),
        json_encode([
            'retry' => 60,
            'refresh' => 60,
        ])
    );

    Event::listen(function (MaintenanceModeDisabled $event) {
        $this->assertTrue(true);
    });

    $this->artisan(UpCommand::class);
}

public function testEnabledEventCanBeListenedTo()
{
    Event::listen(function (MaintenanceModeEnabled $event) {
        $this->assertTrue(true);
    });

    $this->artisan(DownCommand::class);
}

By instantiating the events for dispatch, the events can be listened to using closures. I also couldn't really find anywhere else in the framework where ->dispatch($eventClassNameAsString) was used so hoped that this would be the solution. I wasn't sure if any tests were relevant or required.