Setting mergeConfig breaks scheduler

Just noticed that running the scheduler via `sudo -u www-data -g www-data /usr/bin/php bin/grav scheduler` fails with
```
PHP Fatal error: Uncaught TypeError: Grav\Common\Data\Data::merge(): Argument #1 ($data) must be of type array, Grav\Common\Data\Data given, called in /var/www/html/system/src/Grav/Common/Plugins.php on line 273 and defined in /var/www/html/system/src/Grav/Common/Data/Data.php:203
Stack trace:
#0 /var/www/html/system/src/Grav/Common/Plugins.php(273): Grav\Common\Data\Data->merge()
#1 /var/www/html/system/src/Grav/Common/Plugins.php(231): Grav\Common\Plugins::get()
#2 /var/www/html/system/src/Grav/Common/GPM/Local/Plugins.php(31): Grav\Common\Plugins::all()
#3 /var/www/html/system/src/Grav/Common/GPM/Local/Packages.php(23): Grav\Common\GPM\Local\Plugins->__construct()
#4 /var/www/html/system/src/Grav/Common/GPM/GPM.php(67): Grav\Common\GPM\Local\Packages->__construct()
#5 /var/www/html/user/plugins/update-notifications/update-notifications.php(85): Grav\Common\GPM\GPM->__construct()
#6 /var/www/html/user/plugins/update-notifications/update-notifications.php(67): Grav\Plugin\UpdateNotificationsPlugin::getUpdates()
#7 /var/www/html/user/plugins/update-notifications/update-notifications.php(58): Grav\Plugin\UpdateNotificationsPlugin::getNewUpdates()
#8 /var/www/html/system/src/Grav/Common/Scheduler/Job.php(449): Grav\Plugin\UpdateNotificationsPlugin::run()
#9 /var/www/html/system/src/Grav/Common/Scheduler/Job.php(338): Grav\Common\Scheduler\Job->exec()
#10 /var/www/html/system/src/Grav/Common/Scheduler/Scheduler.php(205): Grav\Common\Scheduler\Job->run()
#11 /var/www/html/system/src/Grav/Console/Cli/SchedulerCommand.php(213): Grav\Common\Scheduler\Scheduler->run()
#12 /var/www/html/system/src/Grav/Console/GravCommand.php(39): Grav\Console\Cli\SchedulerCommand->serve()
#13 /var/www/html/vendor/symfony/console/Command/Command.php(255): Grav\Console\GravCommand->execute()
#14 /var/www/html/vendor/symfony/console/Application.php(1039): Symfony\Component\Console\Command\Command->run()
#15 /var/www/html/vendor/symfony/console/Application.php(275): Symfony\Component\Console\Application->doRunCommand()
#16 /var/www/html/vendor/symfony/console/Application.php(149): Symfony\Component\Console\Application->doRun()
#17 /var/www/html/bin/grav(42): Symfony\Component\Console\Application->run()
#18 {main}
thrown in /var/www/html/system/src/Grav/Common/Data/Data.php on line 203
```
After some debugging I found out that this extension was the problem, to be more specific this line

https://github.com/getgrav/grav-plugin-simplesearch/blob/54fc014ac70cc630278c35929b1000f6c823f7d8/simplesearch.php#L106C13-L106C83

It overwrites the config with another data type. It would work with appending a `->toArray()` after the `mergeConfig` call, but I'm not sure if this is the correct fix, but seems to work for me for the moment.