Fix timeline occasionally breaking on room switch

When a chat page is recycled, set the eventList model to
null, wait for any animations to finish, then explicitely reassign it.
This prevents from model from randomly mixing up old and news delegates.

src/gui/Pages/Chat/Timeline/EventList.qml

@@ -11,6 +11,9 @@ import "../../../PythonBridge"
 import "../../../ShortcutBundles"
 
 Rectangle {
+    readonly property var modelSyncId:
+        [chat.userRoomId[0], chat.userRoomId[1], "events"]
+
     readonly property alias eventList: eventList
     readonly property alias contextMenu: contextMenu
 
@@ -512,7 +515,6 @@ Rectangle {
         // reloaded from network.
         cacheBuffer: Screen.desktopAvailableHeight * 2
 
-        model: ModelStore.get(chat.userRoomId[0], chat.userRoomId[1], "events")
         delegate: EventDelegate {}
 
         highlight: Rectangle {
@@ -555,6 +557,21 @@ Rectangle {
             }
         }
 
+        Connections {
+            target: pageLoader
+            onRecycled: {
+                eventList.model = null
+                updateModelTimer.restart()
+            }
+        }
+
+        Timer {
+            id: updateModelTimer
+            interval: pageLoader.appearAnimation.duration / 2
+            running: true
+            onTriggered: eventList.model = ModelStore.get(modelSyncId)
+        }
+
         Timer {
             interval: 200
             running: