ipatests: run freeipa-healthcheck on hidden replica
    
    Run freeipa-healthcheck on a FreeIPA clusters with a
    hidden replica to make sure a hidden replica is considered
    fully healthy.
    
    Fixes: https://pagure.io/freeipa/issue/8536
    Signed-off-by: François Cami <fcami@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Kaleemullah Siddiqui <ksiddiqu@redhat.com>