OZG-6177 not update configmap if usersYaml isEmpty

Jenkinsfile

...ransfer/user/OzgCloudElsterTransferUserRemoteService.java

...lstertransfer/user/OzgCloudElsterTransferUserService.java

...fer/user/OzgCloudElsterTransferUserRemoteServiceTest.java

...rtransfer/user/OzgCloudElsterTransferUserServiceTest.java