typing_status [nfc]: Remove debugLog for adding self as typist.

This is not prohibited by the server and we should not log expected
behaviors like this.

See:

  https://zulip.com/api/get-events#typing-start

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

lib/model/typing_status.dart

@@ -3,7 +3,6 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 
 import '../api/model/events.dart';
-import '../log.dart';
 import 'narrow.dart';
 
 /// The model for tracking the typing status organized by narrows.
@@ -40,7 +39,6 @@ class TypingStatus extends ChangeNotifier {
 
   bool _addTypist(SendableNarrow narrow, int typistUserId) {
     if (typistUserId == selfUserId) {
-      assert(debugLog('typing status: adding self as typist'));
       return false;
     }
     final narrowTimerMap = _timerMapsByNarrow[narrow] ??= {};