clearer exception handling in OIDCHttpClient::checkOIDCIsAvailable()

lib/main/localizations/app_localizations.dart

@@ -120,6 +120,13 @@ class AppLocalizations {
         args: [errorMessage]);
   }
 
+  String handshakeException(String errorMessage) {
+    return Intl.message(
+      'Handshake error in client: $errorMessage',
+      name: 'handshakeException',
+      args: [errorMessage]);
+  }
+
   String get search_folder {
     return Intl.message(
       'Search folder',

lib/main/utils/toast_manager.dart

@@ -1,3 +1,5 @@
+import 'dart:io';
+
 import 'package:core/domain/exceptions/web_session_exception.dart';
 import 'package:core/presentation/state/failure.dart';
 import 'package:core/presentation/utils/app_toast.dart';
@@ -49,6 +51,8 @@ class ToastManager {
       return AppLocalizations.of(context).notFoundSession;
     } else if (exception is NoNetworkError) {
       return AppLocalizations.of(context).youAreOffline;
+    } else if (exception is HandshakeException) {
+      return AppLocalizations.of(context).handshakeException(exception.osError?.message ?? '');
     } else {
       try {
         return AppLocalizations.of(context).unexpectedError(exception.message);