Complete Telegram bot login from callback URL

lib/auth/telegram_session_stub.dart

@@ -4,18 +4,12 @@ String telegramLoginData() => '';
 
 String mapflowSessionToken() => '';
 
-String pendingTelegramLoginToken() => '';
-
 String telegramLoginTokenFromUrl() => '';
 
 void saveMapflowSessionToken(String token) {}
 
 void clearMapflowSession() {}
 
-void savePendingTelegramLoginToken(String token) {}
-
-void clearPendingTelegramLoginToken() {}
-
 void openExternalUrl(String url) {}
 
 void reloadApp() {}

lib/auth/telegram_session_web.dart

@@ -4,7 +4,6 @@ import 'package:web/web.dart' as web;
 
 const telegramLoginStorageKey = 'mapflow.telegramLoginData';
 const mapflowSessionStorageKey = 'mapflow.sessionToken';
-const pendingTelegramLoginStorageKey = 'mapflow.pendingTelegramLoginToken';
 
 @JS('window.Telegram.WebApp.initData')
 external JSString? get _telegramInitData;
@@ -20,9 +19,6 @@ String telegramLoginData() =>
 String mapflowSessionToken() =>
     web.window.localStorage.getItem(mapflowSessionStorageKey) ?? '';
 
-String pendingTelegramLoginToken() =>
-    web.window.localStorage.getItem(pendingTelegramLoginStorageKey) ?? '';
-
 String telegramLoginTokenFromUrl() {
   final uri = Uri.parse(web.window.location.href);
   return uri.queryParameters['telegram_login'] ?? '';
@@ -40,19 +36,10 @@ void saveMapflowSessionToken(String token) {
 void clearMapflowSession() {
   web.window.localStorage.removeItem(mapflowSessionStorageKey);
   web.window.localStorage.removeItem(telegramLoginStorageKey);
-  clearPendingTelegramLoginToken();
-}
-
-void savePendingTelegramLoginToken(String token) {
-  web.window.localStorage.setItem(pendingTelegramLoginStorageKey, token);
-}
-
-void clearPendingTelegramLoginToken() {
-  web.window.localStorage.removeItem(pendingTelegramLoginStorageKey);
 }
 
 void openExternalUrl(String url) {
-  web.window.open(url, '_blank', 'noopener,noreferrer');
+  web.window.location.assign(url);
 }
 
 void reloadApp() {