Remove deprecation warning from ExtraInputs and ExtraOutputs properties

They cannot be deprecated until there is an alternative method to handle artificial dependencies.

See discussion in !633 (merged)

GaudiKernel/GaudiKernel/DataHandleHolderBase.h

@@ -82,8 +82,8 @@ protected:
 private:
   std::unordered_set<Gaudi::DataHandle*> m_handles;
 
-  Gaudi::Property<DataObjIDColl> m_extInputDataObjs{this, "ExtraInputs", DataObjIDColl{}, "[[deprecated]]"};
-  Gaudi::Property<DataObjIDColl> m_extOutputDataObjs{this, "ExtraOutputs", DataObjIDColl{}, "[[deprecated]]"};
+  Gaudi::Property<DataObjIDColl> m_extInputDataObjs{this, "ExtraInputs", DataObjIDColl{}};
+  Gaudi::Property<DataObjIDColl> m_extOutputDataObjs{this, "ExtraOutputs", DataObjIDColl{}};
 };
 
 #endif // !GAUDIKERNEL_DATAHANDLEHOLDERBASE