MatrixController: Always give information on all rooms

Otherwise element (iOS) will start thinking all DM chats are rooms

lib/pleroma/web/matrix_controller.ex

@@ -292,16 +292,12 @@ def sync(%{assigns: %{user: user}} = conn, params) do
           }
         }
 
-        if length(messages) > 0 do
-          Map.merge(acc, room)
-        else
-          acc
-        end
+        Map.merge(acc, room)
       end)
 
     most_recent_cmr_id =
       Enum.reduce(chats, nil, fn {_k, chat}, acc ->
-        id = List.last(chat.timeline.events).event_id
+        id = List.last(chat.timeline.events)[:event_id]
 
         if !acc || (acc && acc < id) do
           id

test/web/matrix_controller_test.exs

@@ -118,7 +118,7 @@ test "given a `since` option, it only returns chat messages after that point", %
         |> get("_matrix/client/r0/sync?since=#{cmr_two.id}")
         |> json_response(200)
 
-      refute joined_rooms[chat_two.id]
+      assert joined_rooms[chat_two.id]
       assert chat_room = joined_rooms[chat.id]
       assert [message] = chat_room["timeline"]["events"]
       assert message["content"]["body"] == "morning weebs"