fix(ChatMessageView): delayed binding for proper msg height calculation

Direct binding was causing problems with height calculation in some
environments (qt 5.15) and lack of binding in other (5.14). This is
a solution which seems to work in both cases.

Closes: #7703

ui/app/AppLayouts/Chat/views/ChatMessagesView.qml

@@ -251,6 +251,11 @@ Item {
 
             width: ListView.view.width
 
+            Binding on height {
+                delayed: true
+                value: msgDelegate.implicitHeight
+            }
+
             objectName: "chatMessageViewDelegate"
             rootStore: root.rootStore
             messageStore: root.messageStore