ipatests: add missing tests for test_replica_promotion.py
    
    The following test was missing from nightly:
    test_replica_promotion.py::TestReplicaInstallCustodia
    
    Related to https://pagure.io/freeipa/issue/7743
    
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>