Fix EZP-23156: do not throw InvalidArgument exception on empty password
Fix EZP-23156: Add test cases
Fix EZP-23156: add missing exception annotation to UserService::loadUserByCredentials
Merge pull request #930 from joaoinacio/EZP-23156_userlogin_empty_password

Fix EZP-23156: do not throw InvalidArgument exception on empty password