3d-viewer: drop unused m_format member from Export Image dialog

Initialized once to PNG in the constructor, never read or written
anywhere else.


(cherry picked from commit 86f4e4653d)

Co-authored-by: Damjan Prerad <damjan@kipro-pcb.com>

3d-viewer/dialogs/dialog_export_3d_image.cpp

@@ -36,7 +36,6 @@ DIALOG_EXPORT_3D_IMAGE::DIALOG_EXPORT_3D_IMAGE( wxWindow* aParent, const wxSize&
         DIALOG_SHIM( aParent, wxID_ANY, _( "Export 3D View" ), wxDefaultPosition, wxDefaultSize,
                      wxDEFAULT_DIALOG_STYLE ),
         m_cfg( aCfg ),
-        m_format( EDA_3D_VIEWER_EXPORT_FORMAT::PNG ),
         m_originalSize( aCanvasSize ),
         m_width( aCfg && aCfg->width > 0 ? aCfg->width : aCanvasSize.GetWidth() ),
         m_height( aCfg && aCfg->height > 0 ? aCfg->height : aCanvasSize.GetHeight() ),

3d-viewer/dialogs/dialog_export_3d_image.h

@@ -75,7 +75,6 @@ private:
 
 private:
     EDA_3D_VIEWER_SETTINGS::EXPORT_IMAGE_SETTINGS* m_cfg;
-    EDA_3D_VIEWER_EXPORT_FORMAT m_format;
     wxSize m_originalSize;
     int m_width;
     int m_height;