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

diff --git a/packages/flutter_tools/test/version_test.dart b/packages/flutter_tools/test/version_test.dart
index 328e703..312d889 100644
--- a/packages/flutter_tools/test/version_test.dart
+++ b/packages/flutter_tools/test/version_test.dart
@@ -414,7 +414,7 @@
 }
 
 void _expectVersionMessage(String message) {
-  final BufferLogger logger = context[Logger];
+  final BufferLogger logger = context.get<Logger>();
   expect(logger.statusText.trim(), message.trim());
   logger.clear();
 }