refs #21189 [finc] removed mail-container authentication credentials in autoconfig

* but authentication needed for mail client box IMAP:
** server: 127.0.0.1
** port: 11103
** username: dev
** password: dev

docker-env.0.finc.yml

@@ -51,8 +51,6 @@ autoconfig:
       Mail:
         host: mail
         port: 25
-        username: dev
-        password: dev
     searches.ini:
       IndexShards:
         ai: ai.ub.uni-leipzig.de/solr/biblio