related tdf#150557: fix unified transparence initialization with alpha

In 98319164284c4a25d6a2313e6b8a35d244d94e91, shadow alpha
was passed in to UnifiedTransparencePrimitive2D instead of
shadow transparence mistakenly.

Fix that and pass shadow transparence instead.

Change-Id: Idabedade5d753961648683869cb077de0e4523eb
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/156573
Tested-by: Jenkins
Reviewed-by: Sarper Akdemir <sarper.akdemir.extern@allotropia.de>
diff --git a/svx/source/sdr/primitive2d/sdrdecompositiontools.cxx b/svx/source/sdr/primitive2d/sdrdecompositiontools.cxx
index 33e42ef..50f6639 100644
--- a/svx/source/sdr/primitive2d/sdrdecompositiontools.cxx
+++ b/svx/source/sdr/primitive2d/sdrdecompositiontools.cxx
@@ -856,10 +856,8 @@ sal_uInt32 SlideBackgroundFillPrimitive2D::getPrimitive2DID() const
                if (rShadow.getTransparence() != 0.0)
                {
                    Primitive2DContainer aTempContent{ aRetval.back() };

                    double fShadowAlpha = 1.0 - rShadow.getTransparence();
                    aRetval.back() = Primitive2DReference(new UnifiedTransparencePrimitive2D(
                            std::move(aTempContent), fShadowAlpha));
                            std::move(aTempContent), rShadow.getTransparence()));
                }
            }