Merge pull request 'OZG-6979 fix postfach mail error test with json update'...

Merge pull request 'OZG-6979 fix postfach mail error test with json update' (#790) from OZG-6979-Postfach-Fix into master

Reviewed-on: https://git.ozg-sh.de/ozgcloud-app/alfa/pulls/790


Reviewed-by: OZGCloud <ozgcloud@mgm-tp.com>