CADSTAR Schematic: Fix duplicate pins

Fixes a bug that was causing duplicate pins to be loaded
(one on top of the other) for all symbols.

eeschema/sch_plugins/cadstar/cadstar_sch_archive_loader.cpp

@@ -401,6 +401,9 @@ void CADSTAR_SCH_ARCHIVE_LOADER::loadSchematicSymbolInstances()
                 continue;
             }
 
+            if( sym.GateID.IsEmpty() )
+                sym.GateID = wxT( "A" ); // Assume Gate "A" if unspecified
+
             PART_GATE_ID partSymbolID = { sym.PartRef.RefID, sym.GateID };
             LIB_PART*    kiPart = m_partMap.at( sym.PartRef.RefID );
             bool         copy = false;