Adjust German Translation of EU Certificate (#3517)

Old German translation of certificate "EU Digitales COVID-Zertifikat“ is replaced by new official name „Digitales COVID-Zertifikat der EU“. Attention: This is only valid for the German translation. Related Jira issue: https://jira-ibs.wbs.net.sap/browse/EXPOSUREAPP-8014



Co-authored-by: Mohamed Metwalli <mohamed.metwalli@sap.com>