vcl: migrate AddGradientActions() from OutputDevice to Gradient

Change-Id: I815fb3ce366c93b81f60d19eeed906dc7288708a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/127030
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

cppcanvas/source/mtfrenderer/implrenderer.cxx

@@ -720,9 +720,8 @@ namespace cppcanvas::internal
             }
 
             GDIMetaFile aTmpMtf;
-            rParms.mrVDev.AddGradientActions( rPoly.GetBoundRect(),
-                                              rGradient,
-                                               aTmpMtf );
+            Gradient aGradient(rGradient);
+            aGradient.AddGradientActions( rPoly.GetBoundRect(), aTmpMtf );
 
             createActions( aTmpMtf, rParms, bSubsettableActions );