store [nfc]: Use CorePerAccountStore with TypingNotifier

Author: PIG208

lib/model/store.dart

@@ -417,13 +417,7 @@ class PerAccountStore extends PerAccountStoreBase with ChangeNotifier, EmojiStor
         realmUrl: realmUrl, allRealmEmoji: initialSnapshot.realmEmoji),
       accountId: accountId,
       userSettings: initialSnapshot.userSettings,
-      typingNotifier: TypingNotifier(
-        connection: connection,
-        typingStoppedWaitPeriod: Duration(
-          milliseconds: initialSnapshot.serverTypingStoppedWaitPeriodMilliseconds),
-        typingStartedWaitPeriod: Duration(
-          milliseconds: initialSnapshot.serverTypingStartedWaitPeriodMilliseconds),
-      ),
+      typingNotifier: TypingNotifier(core: core),
       users: UserStoreImpl(core: core),
       typingStatus: TypingStatus(core: core),
       channels: channels,

lib/model/typing_status.dart

@@ -2,7 +2,6 @@ import 'dart:async';
 
 import 'package:flutter/foundation.dart';
 
-import '../api/core.dart';
 import '../api/model/events.dart';
 import '../api/route/typing.dart';
 import 'binding.dart';
@@ -92,14 +91,13 @@ class TypingStatus extends PerAccountStoreBase with ChangeNotifier {
 /// See also:
 ///  * https://github.com/zulip/zulip/blob/52a9846cdf4abfbe937a94559690d508e95f4065/web/shared/src/typing_status.ts
 ///  * https://zulip.readthedocs.io/en/latest/subsystems/typing-indicators.html
-class TypingNotifier {
-  TypingNotifier({
-    required this.connection,
-    required this.typingStoppedWaitPeriod,
-    required this.typingStartedWaitPeriod,
-  });
-
-  final ApiConnection connection;
+class TypingNotifier extends PerAccountStoreBase {
+  TypingNotifier({required super.core})
+    : typingStartedWaitPeriod = Duration(milliseconds:
+        core.initialSnapshot.serverTypingStartedWaitPeriodMilliseconds),
+      typingStoppedWaitPeriod = Duration(milliseconds:
+        core.initialSnapshot.serverTypingStoppedWaitPeriodMilliseconds);
+
   final Duration typingStoppedWaitPeriod;
   final Duration typingStartedWaitPeriod;