SDK: Adapt to new DDS plugin external mode

fairmq/sdk/Topology.h

@@ -139,6 +139,7 @@ class Topology
     DDSSession fDDSSession;
     DDSTopology fDDSTopo;
     TopologyState fState;
+    std::unordered_map<uint64_t, DeviceStatus> fStateChangesSubscriptions;
     bool fStateChangeOngoing;
     DeviceState fTargetState;
     mutable std::mutex fMtx;