simplified code across the app and consolidated duplicated helpers

lib/api/errors/error_mapper.dart

@@ -10,9 +10,7 @@ import '../api_error.dart';
 import '../http_errors.dart';
 import '../marianumcloud/talk/talk_error.dart';
 import 'app_exception.dart';
-import 'auth_exception.dart';
 import 'network_exception.dart';
-import 'not_found_exception.dart';
 import 'parse_exception.dart';
 import 'server_exception.dart';
 import 'talk_exception.dart';
@@ -65,23 +63,15 @@ AppException _dynamiteToAppException(DynamiteApiException error) {
   final detail = preview.isEmpty
       ? 'HTTP $status'
       : 'HTTP $status body=$preview';
-  switch (status) {
-    case 401:
-      return AuthException.unauthorized(technicalDetails: detail);
-    case 403:
-      return AuthException.forbidden(technicalDetails: detail);
-    case 404:
-      return NotFoundException(technicalDetails: detail);
-    case 429:
-      return ServerException(
-        statusCode: status,
-        userMessage:
-            'Zu viele Anfragen. Bitte warte einen Moment, bevor du es erneut versuchst.',
-        technicalDetails: detail,
-      );
-    default:
-      return ServerException(statusCode: status, technicalDetails: detail);
+  if (status == 429) {
+    return ServerException(
+      statusCode: status,
+      userMessage:
+          'Zu viele Anfragen. Bitte warte einen Moment, bevor du es erneut versuchst.',
+      technicalDetails: detail,
+    );
   }
+  return exceptionForStatus(status, detail);
 }
 
 String errorToUserMessage(Object? error, {String fallback = _defaultFallback}) {