QmlDesigner: Add an optional close button to the Section

Change-Id: Ia74fc19a10a40290626c20e57150c444d394523d
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Qt CI Patch Build Bot <ci_patchbuild_bot@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

share/qtcreator/qmldesigner/propertyEditorQmlSources/imports/HelperWidgets/Section.qml

@@ -18,6 +18,8 @@ Item {
     property alias showTopSeparator: topSeparator.visible
     property alias showArrow: arrow.visible
     property alias showLeftBorder: leftBorder.visible
+    property alias showCloseButton: closeButton.visible
+    property alias closeButtonToolTip: closeButton.tooltip
     property alias spacing: column.spacing
 
     property int leftPadding: StudioTheme.Values.sectionLeftPadding
@@ -79,6 +81,7 @@ Item {
     signal toggleExpand()
     signal expand()
     signal collapse()
+    signal closeButtonClicked()
 
     DropArea {
         id: dropArea
@@ -157,6 +160,20 @@ Item {
                 }
             }
         }
+
+        IconButton {
+            id: closeButton
+
+            icon: StudioTheme.Constants.close_small
+            buttonSize: 22
+            iconScale: containsMouse ? 1.2 : 1
+            transparentBg: true
+            anchors.right: parent.right
+            anchors.rightMargin: 10
+            visible: false
+
+            onClicked: root.closeButtonClicked()
+        }
     }
 
     Rectangle {