Ensure the bitmap exported to the clipboard is valid.

Fixes #14808
https://gitlab.com/kicad/code/kicad/-/issues/14808

(cherry picked from commit e852d04043)

eeschema/sheet.cpp

@@ -597,6 +597,9 @@ void SCH_EDIT_FRAME::DrawCurrentSheetToClipboard()
 
     PrintPage( cfg );
 
+    // Deselect Bitmap from DC before using the bitmap
+    dc.SelectObject( wxNullBitmap );
+
     {
         wxLogNull doNotLog; // disable logging of failed clipboard actions
 
@@ -610,9 +613,6 @@ void SCH_EDIT_FRAME::DrawCurrentSheetToClipboard()
         }
     }
 
-    // Deselect Bitmap from DC in order to delete the MemoryDC
-    dc.SelectObject( wxNullBitmap );
-
     GRForceBlackPen( false );
 
     screen->m_StartVisu = tmp_startvisu;