improve ParabolicAreas center calculations

--this also fixes the bouncing animation in Tasks
applet when the user applies parabolic zoom on it

containment/package/contents/ui/applet/ParabolicArea.qml

@@ -31,9 +31,7 @@ Item {
     readonly property bool isParabolicEnabled: parabolicAreaLoader.isParabolicEnabled
     readonly property bool isThinTooltipEnabled: parabolicAreaLoader.isThinTooltipEnabled
 
-    property real center:root.isHorizontal ?
-                             (wrapper.width + hiddenSpacerLeft.separatorSpace + hiddenSpacerRight.separatorSpace) / 2 :
-                             (wrapper.height + hiddenSpacerLeft.separatorSpace + hiddenSpacerRight.separatorSpace) / 2
+    property real center: (root.isHorizontal ? appletItem.width : appletItem.height) / 2
 
     MouseArea {
         id: parabolicMouseArea

declarativeimports/abilities/items/basicitem/ParabolicItem.qml

@@ -65,7 +65,7 @@ Item{
     property real visualScaledThickness: abilityItem.abilities.metrics.totals.thickness * zoom
     /// end of Scalers///////
 
-    property real center: ((abilityItem.isHorizontal ? width : height) + hiddenSpacerLeft.separatorSpace + hiddenSpacerRight.separatorSpace) / 2
+    property real center: (abilityItem.isHorizontal ? abilityItem.width : abilityItem.height) / 2
 
     readonly property alias contentItemContainer: _contentItemContainer
     readonly property alias titleTooltipVisualParent: _titleTooltipVisualParent