remove the export from api

Author: cynthiajoan

packages/firebase_ai/firebase_ai/lib/src/api.dart

@@ -17,7 +17,6 @@ import 'error.dart';
 import 'image_config.dart';
 import 'schema.dart';
 import 'tool.dart' show Tool, ToolConfig;
-export 'image_config.dart';
 
 /// Response for Count Tokens
 final class CountTokensResponse {

packages/firebase_ai/firebase_ai/test/api_test.dart

@@ -18,6 +18,7 @@ import 'dart:convert';
 import 'package:firebase_ai/src/api.dart';
 import 'package:firebase_ai/src/content.dart';
 import 'package:firebase_ai/src/error.dart';
+import 'package:firebase_ai/src/image_config.dart';
 import 'package:firebase_ai/src/schema.dart';
 import 'package:flutter_test/flutter_test.dart';