Gets language code of the job item source.
\Drupal\tmgmt\JobItemInterface $job_item: The job item.
string|false Language code or FALSE for unknown.
Overrides SourcePluginInterface::getSourceLangCode
public function getSourceLangCode(JobItemInterface $job_item) {
$config_mapper = $this
->getMapper($job_item);
return $config_mapper
->getLangcode();
}