Fixes compound mesh failur [spns 24411]

 Fixes compound mesh failur [spns 24411]
Since gmsh version 4.3 when compund meshing is involved Gmsh
produces extra discrete surfaces apart from the original topology
 Gmsh meshing procedure needs acess to each of the original topology
and the meshed topology.

Hence we bypass the additional DiscreteSurface mesh in case compound
meshing is involved. This bypass is needed during the GMSHPlugin_Mesher::FillSMesh()