fix(storage): add ClientException to imports

Add ClientException to the explicit imports from package:http/http.dart
to fix analyzer error: type_test_with_undefined_name

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: grdsdev

packages/storage_client/lib/src/fetch.dart

@@ -3,7 +3,8 @@ import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:http/http.dart' as http;
-import 'package:http/http.dart' show Client, MediaType, MultipartFile;
+import 'package:http/http.dart'
+    show Client, ClientException, MediaType, MultipartFile;
 import 'package:logging/logging.dart';
 import 'package:mime/mime.dart';
 import 'package:retry/retry.dart';