BitmapEx->Bitmap in MetaBmpExAction

now that Bitmap supports transparency

Note that the SVM unit test changed because we no longer
store some bitmaps as an 8-bit palette color layer and an
8-bit alpha layer. When those pass through Bitmap, they
get converted to a 32-bit bitmap.

Change-Id: Icbb30e291a7ed5c53319876637ae25e88a97d90d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/190330
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins

cppcanvas/source/mtfrenderer/implrenderer.cxx

@@ -2188,7 +2188,7 @@ namespace cppcanvas::internal
 
                         std::shared_ptr<Action> pBmpAction(
                                 internal::BitmapActionFactory::createBitmapAction(
-                                    Bitmap(pAct->GetBitmapEx()),
+                                    pAct->GetBitmap(),
                                     rStates.getState().mapModeTransform *
                                     vcl::unotools::b2DPointFromPoint( pAct->GetPoint() ),
                                     rCanvas,