fix: prevent ListView overscroll in notification panel

Added overscroll protection to the notification center ListView to
prevent unwanted bounce-back behavior when scrolling beyond content
boundaries. The fix includes three event handlers that monitor height,
content height, and content position changes to ensure the scroll
position stays within valid bounds.

Implemented bounds checking in onHeightChanged, onContentHeightChanged,
and onContentYChanged handlers to clamp the contentY position when it
exceeds the content boundaries. This prevents the ListView from showing
empty space when scrolled beyond the actual content area, which was
causing visual glitches and inconsistent scrolling behavior.

Influence:
1. Test scrolling to the top and bottom of notification list
2. Verify no empty space appears when reaching content boundaries
3. Check that normal scrolling behavior remains smooth
4. Test with various numbers of notifications (empty, few, many)
5. Verify scroll position is maintained during content updates

PMS: BUG-284867

Author: caimc123456

panels/notification/center/NotifyView.qml

@@ -61,7 +61,7 @@ Control {
         id: view
         clip: true
         spacing: 10
-        snapMode: ListView.SnapToItem
+        snapMode: ListView.NoSnap
         keyNavigationEnabled: false
         activeFocusOnTab: false
         boundsBehavior: Flickable.StopAtBounds