[SDESK-4466] (fix): Use default locale for translations if user language is not supported (#1623)
[SDESK-4466] (fix): Use default locale for translations if user language is not supported (#1623)


superdesk/superdesk-core,petrjasek/superdesk-core,superdesk/superdesk-core,superdesk/superdesk-core,petrjasek/superdesk-core,petrjasek/superdesk-core,petrjasek/superdesk-core,superdesk/superdesk-core