Show LeftBanner with a generic left text

src/qml/EventHandlers/rooms.js

@@ -25,7 +25,7 @@ function typingTextFor(members, our_user_id) {
 
 function onRoomUpdated(
     user_id, category, room_id, display_name, avatar_url, topic,
-    typing_members, inviter_id, left_event
+    typing_members, inviter_id
 ) {
     roomCategories.upsert({"userId": user_id, "name": category}, {
         "userId": user_id,
@@ -50,8 +50,7 @@ function onRoomUpdated(
         "avatarUrl":   avatar_url,
         "topic":       topic,
         "typingText":  typingTextFor(typing_members, user_id),
-        "inviterId":   inviter_id,
-        "leftEvent":   left_event ? py.getattr(left_event, "__dict__") : {},
+        "inviterId":   inviter_id
     })
 }