fix: schedule:test on commands using runInBackground (#54321)

Force to run the selected command in the foreground.

The `artisan schedule:test` command exited immediately after invocation
and the selected command did not start if it uses `->runInBackground()`.
If `->withoutOverlapping()` is used too, the mutex would not be removed
and blocks any further execution without any user facing notice.

src/Illuminate/Console/Scheduling/ScheduleTestCommand.php

@@ -76,9 +76,11 @@ public function handle(Schedule $schedule)
         $description = sprintf(
             'Running [%s]%s',
             $command,
-            $event->runInBackground ? ' in background' : '',
+            $event->runInBackground ? ' normally in background' : '',
         );
 
+        $event->runInBackground = false;
+
         $this->components->task($description, fn () => $event->run($this->laravel));
 
         if (! $event instanceof CallbackEvent) {