Direct access to mapdl_element_type

Hi Ramdane,

as requested I create this issue. It would be great to get direct access to the mapdl_element_type for all elements of a mesh region.
At the moment I can only get access to the generalized element types (result_mesh.elements.element_types_field).

Start by tracing result_mesh.elements.element_types_field and how mesh-region elements expose their generalized types. Determine where the underlying mapdl_element_type data is represented, then verify that direct access returns it for every element in a mesh region.

Written by the indexing model from the issue text.