[6.x] Remove hardcoded Carbon reference from scheduler event

[axlon]

This pull request changes the date that is used to check if a scheduled event is due to the Date facade. I ran into a problem where my tests are failing because my application uses a different date class (CarbonImmutable)

class AppServiceProvider extends ServiceProvider
{
    public function boot(): void
    {
        Date::use(CarbonImmutable::class);
    }
}

class MyTest extends TestCase
{
    public function testScheduler(): void
    {
        Date::setTestNow('...');

        $myEvent = '...';
        $dueEvents = $this->app->make(Schedule::class)->dueEvents($this->app);

        // This next line fails, because Carbon::now() returns the actual date
        $this->assertTrue($dueEvents->contains($myEvent));
    }
}

The following test will always fail because the scheduler calls Carbon directly, which at this point does not have a test instance set (because CarbonImmutable is used)

This shouldn't introduce any breaking changes because:

• illuminate/console already requires illuminate/support
• The \Illuminate\Console\Scheduling\Event class already uses the Date facade everywhere except the line that was changed