refactor context to be implicit-downcast safe (#31622)

diff --git a/packages/flutter_tools/lib/src/android/android_sdk.dart b/packages/flutter_tools/lib/src/android/android_sdk.dart
index d8a7326..65f40aa 100644
--- a/packages/flutter_tools/lib/src/android/android_sdk.dart
+++ b/packages/flutter_tools/lib/src/android/android_sdk.dart
@@ -17,7 +17,7 @@
 import '../globals.dart';
 import 'android_studio.dart' as android_studio;
 
-AndroidSdk get androidSdk => context[AndroidSdk];
+AndroidSdk get androidSdk => context.get<AndroidSdk>();
 
 const String kAndroidHome = 'ANDROID_HOME';
 const String kAndroidSdkRoot = 'ANDROID_SDK_ROOT';