frontend: copy command arguments to output params on client
    
    In commit f554078291d682d59956998af97f7d3066fbe7e7 we stopped copying
    command arguments to output params in order to remove redundancies and
    reduce API schema in size. Since then, output params were removed from
    API schema completely and are reconstructed on the client.
    
    Not including arguments in output params hides failed members from member
    commands' CLI output. To fix this, copy arguments to output params again,
    but only on the client side.
    
    https://fedorahosted.org/freeipa/ticket/6026
    
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>