kcms/rules: Fix section header and info button sizing

The section header being now a QQC2.ItemDelegate needs to explicitly
set the width to be visible.

The ContextualHelpButton size was getting constrained by the parent
layout's being adjusted to just the label height.

src/kcms/rules/ui/RuleItemDelegate.qml

@@ -35,6 +35,7 @@ QQC2.ItemDelegate {
 
         RowLayout {
             Layout.preferredWidth: 10 * Kirigami.Units.gridUnit
+            Layout.preferredHeight: Kirigami.Units.iconSizes.medium
             spacing: Kirigami.Units.smallSpacing
 
             QQC2.Label {
@@ -56,7 +57,6 @@ QQC2.ItemDelegate {
             }
 
             KCM.ContextualHelpButton {
-                Layout.preferredHeight: Kirigami.Units.gridUnit * 2
                 Layout.alignment: Qt.AlignVCenter
                 visible: model.description.length > 0
                 toolTipText: model.description

src/kcms/rules/ui/RulesEditor.qml

@@ -190,6 +190,7 @@ KCM.ScrollViewKCM {
                 property: "section"
                 delegate: Kirigami.ListSectionHeader {
                     label: section
+                    width: ListView.view.width
                     height: implicitHeight
                 }
             }