Fixed some more warnings, moved function to get ExtrusionRole name into ExtrusionEntity.hpp

So it can be called from wherever it may be needed

src/slic3r/GUI/GLCanvas3D.hpp

@@ -433,7 +433,6 @@ private:
     bool m_initialized;
     bool m_apply_zoom_to_volumes_filter;
     mutable std::vector<int> m_hover_volume_idxs;
-    bool m_warning_texture_enabled;
     bool m_legend_texture_enabled;
     bool m_picking_enabled;
     bool m_moving_enabled;