Create NeochatRoomMember as a shim for RoomMember

The intention is that NeochatRoomMember can be created passed to QML and then be fully managed by it. It effectively just grabs the current RoomMember, calls the correct function then discards it so that we don't end up trying to access an already deleted state event.

src/timeline/HiddenDelegate.qml

@@ -26,7 +26,7 @@ TimelineDelegate {
     /**
      * @brief The message author.
      */
-    required property RoomMember author
+    required property NeochatRoomMember author
 
     width: parent?.width
     rightPadding: NeoChatConfig.compactLayout && root.ListView.view.width >= Kirigami.Units.gridUnit * 20 ? Kirigami.Units.gridUnit * 2 + Kirigami.Units.largeSpacing : Kirigami.Units.largeSpacing
@@ -88,7 +88,7 @@ TimelineDelegate {
     QtObject {
         id: _private
         function showMessageMenu() {
-            RoomManager.viewEventMenu(root.eventId, root.room, "");
+            RoomManager.viewEventMenu(root.eventId, root.room, root.author, "");
         }
     }
 }