fix: use foreground color for icon default

AppIcon.qml

@@ -4,7 +4,7 @@ import QtQuick.Controls.Basic
 Item {
     id: item
     required property string source
-    property color color: "white"
+    property color color: Theme.foreground
     required property int iconHeight
     required property int iconWidth
     property var onClicked

gallery/Main.qml

@@ -152,6 +152,11 @@ AppWindow {
 
                 // NOTE: MenuItem is not recommended as it isn't consistent with the menu theming. Please use Action until a fix is made.
             }
+            AppIcon {
+                source: "qrc:/live.flowy/imports/DesignSystem/icons/sidebar-duotone.svg"
+                iconWidth: 10
+                iconHeight: 10
+            }
             AppSecondaryButton {
                 onClicked: menu.open()
                 text: "Open menu"