fix volume panel disappearing: use animateHeight, remove inner height animation

modules/Volume.qml

@@ -107,6 +107,7 @@ M.BarSection {
         accentColor: root.accentColor
         panelNamespace: "nova-volume"
         contentWidth: 220
+        animateHeight: true
 
         // Compact: slider row
         Item {
@@ -230,16 +231,6 @@ M.BarSection {
             id: deviceList
             width: parent.width
             visible: root._expanded
-            clip: true
-
-            property real _targetHeight: root._expanded ? implicitHeight : 0
-            height: _targetHeight
-            Behavior on height {
-                NumberAnimation {
-                    duration: 200
-                    easing.type: Easing.OutCubic
-                }
-            }
 
             // Separator
             Rectangle {