ConfigSplitCliService::export() does not check if the config data exists

On line 301 of ConfigSplitCliService::export(), the write is called directly with read for the active storage. This can cause issues when deploying to an older database and attempting to export a database config split.

299:     // Copy everything.
300:     foreach ($active->listAll() as $name) {
301:       $storage->write($name, $active->read($name));

Error thrown:

TypeError: Argument 2 passed to Drupal\config_filter\Config\FilteredStorage::write() must be of the type array, boolean given, called in /modules/contrib/config_split/src/ConfigSplitCliService.php on line 301 in Drupal\config_filter\Config\FilteredStorage->write() (line 94 of /modules/contrib/config_filter/src/Config/FilteredStorage.php).