Import flutter_test for future compatibility

The service mocks are going to move from services.dart to flutter_test/.

Author: Hixie

packages/camera/camera/test/utils/method_channel_mock.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
 
 class MethodChannelMock {
   final Duration? delay;

packages/camera/camera_platform_interface/test/utils/method_channel_mock.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
 
 class MethodChannelMock {
   final Duration? delay;

packages/in_app_purchase/test/in_app_purchase_connection/app_store_connection_test.dart

@@ -6,9 +6,8 @@ import 'dart:async';
 import 'dart:io';
 
 import 'package:flutter/services.dart';
-import 'package:flutter_test/flutter_test.dart' show TestWidgetsFlutterBinding;
+import 'package:flutter_test/flutter_test.dart';
 import 'package:in_app_purchase/src/in_app_purchase/purchase_details.dart';
-import 'package:test/test.dart';
 
 import 'package:in_app_purchase/src/channel.dart';
 import 'package:in_app_purchase/src/in_app_purchase/app_store_connection.dart';

packages/in_app_purchase/test/in_app_purchase_connection/google_play_connection_test.dart

@@ -5,9 +5,8 @@
 import 'dart:async';
 
 import 'package:flutter/services.dart';
-import 'package:flutter_test/flutter_test.dart' show TestWidgetsFlutterBinding;
+import 'package:flutter_test/flutter_test.dart';
 import 'package:in_app_purchase/src/in_app_purchase/purchase_details.dart';
-import 'package:test/test.dart';
 
 import 'package:flutter/widgets.dart' as widgets;
 import 'package:in_app_purchase/billing_client_wrappers.dart';

packages/sensors/test/sensors_test.dart

@@ -5,9 +5,8 @@
 import 'dart:typed_data';
 
 import 'package:flutter/services.dart';
-import 'package:flutter_test/flutter_test.dart' show TestWidgetsFlutterBinding;
+import 'package:flutter_test/flutter_test.dart';
 import 'package:sensors/sensors.dart';
-import 'package:test/test.dart';
 
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();