[ExpandableListItem] Make expanded actions list view respect font

Previously it was basing its height on an icon size, which does not
scale with the font. As a result, sometimes the actions list could
get clipped when using certian fonts and font sizes. Let's change this
to multiples of GridUnit, which adjusts with the font.

src/declarativeimports/plasmaextracomponents/qml/ExpandableListItem.qml

@@ -508,7 +508,7 @@ Item {
                 anchors.leftMargin: listItemIcon.width + PlasmaCore.Units.smallSpacing
                 anchors.rightMargin: listItemIcon.width + PlasmaCore.Units.smallSpacing * 2
 
-                height: (PlasmaCore.Units.iconSizes.smallMedium + PlasmaCore.Units.smallSpacing * 2) * actionsList.count
+                height: PlasmaCore.Units.gridUnit * 2 * actionsList.count
 
                 focus: true
                 clip: true